Methods And Issues Of Studying The Brain In Psychology

METHODS AND ISSUES OF STUDYING THE BRAIN IN PSYCHOLOGY Kevin Brewer

ISBN: 978-1-904542-48-3

This document is produced under two principles: 1. All work is sourced to the original authors. The images are all available in the public domain (most from http://commons.wikimedia.org/wiki/Main_Page). You are free to use this document, but, please, quote the source (Kevin Brewer 2009) and do not claim it as you own work. This work is licensed under the Creative Commons Attribution (by) 3.0 License. To view a copy of this license, visit http://creativecommons.org/licenses/by-ncnd/3.0/ or send a letter to Creative Commons, 171 2nd Street, Suite 300, San Francisco, California, 94105, USA.

2. Details of the author are included so that the level of expertise of the writer can be assessed. This compares to documents which are not named and it is not possible to tell if the writer has any knowledge about their subject. Kevin Brewer BSocSc, MSc An independent academic psychologist, based in England, who has written extensively on different areas of psychology with an emphasis on the critical stance towards traditional ideas. Orsett Psychological Services, PO Box 179, Grays, Essex RM16 3EW UK [email protected] (http://kmbpsychology.jottit.com) or (http://psyman.weebly.com)

Methods and Issues of Studying the Brain in Psychology; Kevin Brewer; 2009 ISBN: 978-1-904542-48-3

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CONTENTS Page Number 1. Introduction

5

2. Studying the Brain Outside the Body

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2.1. Tissue or cell culture 2.2. Post mortems

7 9

3. Studying Non-Human Animals 3.1. Olds and Milner (1954) 3.2. Key arguments for studying non-human animals to understand humans 3.3. Key arguments against studying non-human animals to understand humans

4. Intervention Techniques 4.1. Destruction of brain tissue 4.1.1. Psychosurgery 4.1.2. Brain lesions - example with animals: Lashley (1931) 4.2. Split brain patients 4.3. Artificial stimulation 4.3.1. Wilder Penfield 4.3.2.Studying temporal aspects of perception

5. Naturally Occurring Brain Damage 5.1. Brain injury/damage from birth 5.2. Acquired brain injury/damage 5.2.1. Phineas Gage 5.3. Brain injury/damage through illness 5.3.1. Clive Wearing

6. Recording Electrical Activity 6.1. Electroencephalogram 6.2. Evoked potentials or Methods and Issues of Studying the Brain in Psychology; Kevin Brewer; 2009 ISBN: 978-1-904542-48-3

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18 18 19 21 24 28 29 34

37 37 37 38 41 44

47 47

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event-related potentials 6.3. Magnetoencephalography 6.4. Single unit recording

7. Computer Tomography/Neuorimaging 7.1. Computerised axial tomography 7.2. Positron emission tomography 7.2.1 Single-photon emission computerised tomography 7.2.2. Hippocampus and London taxi drivers 7.3. Nuclear magnetic resonance imaging 7.4. Magnetic resonance spectroscopy 7.5. Functional magnetic resonance imaging 7.6. Ethical issues and neurimaging

47 48 48

50 52 53 55 55 58 59 59 60

8. New and Miscellaneous Techniques

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9. Issues and Debates

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9.1. Mind-brain relationship 9.2. Conscious and not conscious

66 69

10. References

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11. Appendix

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Methods and Issues of Studying the Brain in Psychology; Kevin Brewer; 2009 ISBN: 978-1-904542-48-3

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1. INTRODUCTION The brain has been studied in psychology using a number of different methods over time and currently: i) Studied in detail outside the body as with postmortem brains, and in tissue cultures; ii) Through studying the brains of non-human animals; iii) Intervention and artificial stimulation techniques that deliberately damages or alter the brain in some way; iv) Studying case studies of naturally occurring brain injury and damage; v) Recording of electrical activity as with electroencephalography (EEG); vi) Modern technological methods of computer tomography and neuroimaging - computerised axial tomography (CAT), positron emission tomography (PET), single-photon emission tomography (SPECT), magnatic resonance imaging (MRI), functional magnetic imaging (fMRI), and magnetic resonance spectroscopy (MRS); There are many different ways used to study the brain, but they can be classified as:


Invasive/non-invasive - whether the researcher goes inside the skull (table 1);




Intervening with the brain's normal functioning or not (table 2);




Studying the active or the static live brain, or the dead brain (table 3);




Studying the structure or function of the brain (table 4).

INVASIVE

NON-INVASIVE












Animal studies Artificial stimulation Destruction Post-mortems




Patients with brain damage Tissue culture Transcranial Magnetic Stimulation (TMS) Tomography

Table 1 - Examples of invasive and non-invasive methods of studying the brain. Methods and Issues of Studying the Brain in Psychology; Kevin Brewer; 2009 ISBN: 978-1-904542-48-3

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INTERVENTION

NON-INTERVENTION













Animal studies Artificial stimulation Destruction TMS

Patients with brain damage Post-mortems Tissue culture Tomography

Table 2 - Methods of studying the brain involving intervention or not.

ACTIVE LIVE BRAIN

STATIC LIVE BRAIN

DEAD BRAIN





















Animal studies Artificial stimulation Destruction Electrical recording fMRI Patients with brain damage PET scans MEG TMS

CAT scans MRI

Post-mortems

Table 3 - Methods studying the active or static live brain, and the dead brain.

STRUCTURE

FUNCTION

BOTH




















CAT scans MRI

Artificial stimulation Destruction Electrical recording fMRI Patients with brain damage PET scans MEG Tissue culture TMS

Animal studies Post-mortems

Table 4 - Methods studying the structure and function of the brain.

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2. STUDYING THE BRAIN OUTSIDE THE BODY One way to study the brain, and overcome the problem of accessibility, is outside the body. This is done with tissue or cell culture (live) and post-mortems (dead tissue). 2.1. TISSUE OR CELL CULTURE A small amount of brain tissues or cells can be kept alive outside the body as tissue or cell cultures. These are known as "in vitro" (outside the body) compared to "in vivo" (inside the body)(Whatson 2004). The cells or tissues continue to grow in nutrients (table 5). Some cultures can continue to grow as long as required ("immortalized cell lines") while others have a limited lifespan (Whatson 2004). A typical experiment involves stimulating a particular cell, like a Purkinje cell from the cerebellum (figure 1), in different ways to see the response (Whatson 2004). STRENGTHS 1. Ideal for the study of specific cells and their physiology. 2. The cells are alive and so have advantages over post-mortem tissue, like responsiveness to stimuli. 3. No ethical concerns as with live participants. 4. Overcomes problems of studying these cells "in vivo". WEAKNESSES 1. The study of individual cells without the normal interactions in the brain. It is like studying a city by concentrating on one person only. 2. Isolated cells behave differently in nutrients than in situ (inside the brain) like maintaining their usual structure. 3. Very reductionist - trying to understand the complexity of the whole brain from individual cells. 4. How are the cells and tissues obtained? Probably by use of an invasive technique like brain surgery.

Table 5 - Strengths and weaknesses of using tissue or cell culture to study the brain.

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Purkinje cells - green (Source: Sbrander; in public domain)

Figure 1 - Mouse cerebellum seen with laser scanning microscope. 2.2. POST-MORTEMS Historically, this was the first method used to study the brain. The brain of the dead person (or animal) is examined. It "remains the gold standard" method because of the ability to study genetic, molecular, cellular, and neurochemical aspects (Deep-Soboslay et al 2005). This gives it advantage over the other methods of study of non-human animals, or of live humans in neuroimaging studies (table 6). The brain can be sliced to reveal the internal parts as well as evidence of abnormalities in size or shape, and tumours, for example. Methods and Issues of Studying the Brain in Psychology; Kevin Brewer; 2009 ISBN: 978-1-904542-48-3

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There is a routine 48-hour interval between death and the post-mortem (Harrison 1996). STRENGTHS 1. Overcomes limitations of using other methods with animals to study human behaviour. 2. More detailed examination of genetic, molecular, cellular, and neurochemical aspects of the brain than neuroimaging of live participants. 3. Used to study brain structure as well as biochemistry. 4. Gains details that non-invasive studies cannot, like the ability to study individual parts of the brain under a microscope. 5. No concerns about the ethics of treatment as with live participants. 6. Non-intervention method which can be used with humans and nonhuman animals. 7. Able to investigate the internal parts of the brain. 8. Complex techniques, like immunohistochemistry, aid the understanding of brain chemistry. WEAKNESSES 1. Death may cause changes for the brain. 2.




Confounding variables include: Peri-mortem (ie: before death); eg: fever as cause of death; Post-mortem; eg: method of storing body after death; Miscellaneous; eg: age of individual, smoker, drug addict.

3. Not possible to establish cause and effect relationships as in experiments with live participants. 4. Problems of retrospective diagnosis of problems after death. 5. Reductionist - studies individual parts, even cells, and not the whole brain. 6. Dead tissue decays and dries out quickly even with a speedy preservation process. 7. The brain has to be preserved by chemicals, like formalin. Brain slices are often stained by Golgi stain or horseradish peroxidase to aid microscopy (Whatson 2004). These processes alter the brain. 8. Methods using live human participants allows them to talk about their sensations and thoughts while the brain is being studied. This is not possible with post-mortems or studies with non-human animals.

Table 6 - Strengths and weaknesses of studying the brain using post-mortems.

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The best known examples of discoveries about the brain using the post-mortem method with human brains relate to Broca's and Wernicke's areas (figure 2). In 1861, Paul Broca (figure A appendix) reported the case of "Tan" (box 1). This was a man who could only say "tantan", but had a fuller understanding of speech (known now as expressive aphasia). The post-mortem of "Tan" found damage in the left frontal lobe in a region now known as Broca's area. Wernicke's area in the left temporal lobe is named after Carl Wernicke who studied stroke patients able to speak, but who had problems with language comprehension (known now as receptive aphasia).

(Source: US Federal Government; in public domain; http://www.nidcd.nih.gov/health/voice/aphasia.asp)

Figure 2 - Broca's and Wernicke's areas. Complex techniques today using electron microscopy allow researcher to understand the biochemistry of the brain (Whatson 2004):


Immunohistochemistry - washing brain slices in certain fluids highlights antibodies, for example, present. Antibodies are reactions to attacks on the immune system and are taken as evidence of diseases;




Autoradiography - radioactive substances can be used to show what substances are within the brain tissue;




In situ hybridization - this can locate proteins in the brain tissue.

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"Tan" was 51 years old when he died on 17th April, 1861 at Bicetre hospital in France, and he had lost his speech before 21 years old (when first seen at the hospital). He was also paralysed on the right side. His intelligence was affected to "a great degree" "but he maintained certainly more of it than was needed for talking". He answered some questions with gestures, and others not at all (even when the answer was obvious). At the autopsy, the dura mater was found to be thickened and vascularised, covered on the inside with a thick pseudo-membranous layer; the pia mater thick, opaque, and adherent to the anterior lobes particularly the left lobe. The frontal lobe of the left hemisphere was soft over a great part of its extent; the convolutions of the orbital region, although atrophied, preserved their shape; most of the other frontal convolutions were entirely destroyed. The result of this destruction of the cerebral substance was a large cavity, capable of holding a chicken egg, and filled with serous fluid. The softness had spread up to the ascending fold of the parietal lobe, and down to the marginal fold of the temporalsphenoidal lobe; finally, in the depths, [it spread to] the region of the insula and the extraventricular nucleus of the striate body; it was the lesion of this last organ which was responsible for the paralysis of the movement of the two limbs of the right side. However, it suffices to cast a glance at this paper to recall that the principal home and the original seat of the softness, is the middle part of the frontal lobe of the left hemisphere; it is there than one find the most extensive lesions -- the most advanced and the oldest. The softness progressed very slowly to the adjoining parts and one can regard it as certain that it was there for a very long period. [p. 238] during which the illness did not affect the convolutions of the frontal lobe. This period probably corresponds to the eleven years that preceded the paralysis of the right arm, and during which the patient had maintained his intelligence, having lost nothing other than speech. All this permits, however, the belief that, in the present case, the lesion of the frontal lobe was the cause of the loss of speech (Broca 1861 pp237-8; translated by Christopher. D. Green 2003; http://psychclassics.yorku.ca/index.htm).

Box 1 - Details of post-mortem of "Tan" by Paul Broca (1861). In terms of the biochemistry of the human brain, Owen et al's (1978) study of the brains of sufferers from schizophrenia after death found an excess of the receptors for the neurotransmitter, dopamine, in the limbic system. Specifically, more D2 receptors than in the brains of non-schizophrenic individuals.

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3. STUDYING NON-HUMAN ANIMALS Non-human animals can be studied in ways similar to humans or in cases where it is not possible to study humans. Often non-human animals are used where direct intervention is required. Table 7 compares the methods used to study the brain of human and non-human animals. METHOD

SAME

Post-mortems

yes

DIFFERENT

Destruction

Larger areas than with humans

Artificial stimulation

Greater risks than with humans and less concern about side effects, including death

Table 7 - Methods used to study the brain of human and non-human animals. Home Office (2005) data showed that in all licensed scientific experiments in 2005, 20 542 animals had "interference with brain" and 13 978 "injection into brain". The most common animals used were rats and mice. These figures relate to all scientific research, not just psychology nor only to study the brain. There are both strengths and weaknesses in studying non-human animals to understand the human brain (table 8). STRENGTHS 1. Non-human animals can be used in ways unacceptable with humans. 2. A "shared biological heritage" between human and non-human animals. 3. The whole process of development can be observed in animals with short lifespans. 4. Greater control over variables by keeping animals in standard laboratory cages. 5. Gives ideas for research with humans. 6. Benefits from research findings for humans.

WEAKNESSES 1. The physiology of non-human animals is not exactly the same as humans. 2. The morality of using animals in experiments. Methods and Issues of Studying the Brain in Psychology; Kevin Brewer; 2009 ISBN: 978-1-904542-48-3

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3. The ethics of inflicting pain and suffering upon animals in experiments. 4. Human and non-human animals are different in a number of ways including the use of language, and flexibility in learning. 5. Animals are kept and studied in the artificial environment of the laboratory. 6. There are alternative methods available which involve studying humans to understand the human brain.

Table 8 - Strengths and weaknesses of studying non-human animals for understanding the human brain in psychology. 3.1. OLDS AND MILNER (1954) In a classic experiment, Olds and Milner (1954) placed electrodes in the brains of fifteen male hooded rats in order to stimulate particular areas of the brain. Under anaesthesia, the 0.010 inch diameter electrodes were implanted in the brain and attached to a block cemented on the skull and wires through which the minute electrical signals (0.5-5 volts) were sent. Straight after testing, which occurred three days after the operation, the animals were killed ("sacrificed") in order to perform a post-mortem study of the brain. Different areas of the brain were implanted in order to see how the rats responded to stimulation of the areas. The research concentrated on, what was later called, the "reward" or "pleasure centre" (Olds 1956) of the brain. The rats would press the lever frequently to receive stimulation to electrodes in that area of the brain (in forebrain). For example, "rat no.32" pressed the lever over 3000 times in twelve hours, and "rat no.34" 75000 times in the same period. This is known as electrical self-stimulation of the brain" (ESB). Table 9 lists the main strengths and weaknesses of the research by Olds and Milner (1954). STRENGTHS 1. Controlled environment of the experiment including implanting of electrodes and testing. 2. Both overt behaviour was observed (lever pressing) and the effect upon the brain (post-mortem study). 3. Able to isolate areas of the brain involved in feelings of "pleasure" and "reward". 4. Animals not deprived of food and water during the experiment.

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WEAKNESSES 1. The effects of the operation upon the rats' brain (ie: damage caused other than implanting the electrodes). 2. The rats' lives ended immediately after testing for post-mortem study. The ethics and morality of such behaviour by the researchers. 3. Not studying "natural" behaviour as rats inhibited by, for example, wires attached to skull. 4. A small number of rats were used, and different areas of the brain tested (eg: 4 rats had electrodes in septal area, one rat in hippocampus).

Table 9 - Strengths and weaknesses of experiment by Olds and Milner (1954). 3.2. KEY ARGUMENTS FOR STUDYING NON-HUMAN ANIMALS TO UNDERSTAND HUMANS 1. It is possible to use invasive techniques that would be unacceptable with humans. This includes the destruction of larger areas of the brain, and greater levels of artificial stimulation without concern for the side effects or consequences. In other words, it is not seen as an issue if the animal dies, which is not possible with human participants. 2. In terms of physiology, non-human and human animals are the same. The biology of the brain is the same with common evolutionary origins, even if the human brain has developed further than other mammals. This is called the "shared biological heritage". For example, dopamine in the substantia nigra area of the brain controls movement in the same way in rats and humans (Whatson 2004). There are also common ailments and diseases. For example, narcolepsy (sleep disorder) occurs in both humans and certain breeds of dogs (Whatson 2004). 3. Non-human animals with short lifespans allow researchers to study the whole proces of development and several generations. Such animals can be kept in controlled environments which limit outside influences and confounding variables. Thus the mouse is seen as an ideal candidate to study with its short lifespan, rapid maturation, multiple offspring, documented genetics, and ease of housing (Whatson 2004). But Baldwin and Berkoff (2007) reported evidence that standard laboratory conditions used with mice and Methods and Issues of Studying the Brain in Psychology; Kevin Brewer; 2009 ISBN: 978-1-904542-48-3

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rats caused stress, enough to affect the animals' physiology, and this produced a major confounding variable. 3.3. KEY ARGUMENTS AGAINST STUDYING NON-HUMAN ANIMALS TO UNDERSTAND HUMANS 1. Non-human animals are not exactly the same as humans in terms of physiology. For example, comparison of visual processing in the brain of rhesus monkeys and humans found similarities, but also key differences in "the higher-order areas of the association cortex" (Orban et al 2004). The study of non-human animals to aid the understanding of humans is based upon the assumption that similar physiology and genes do the same things in different species. In the case of genes, similar genes in different species are said to be orthologous (Liao and Zhang 2008). But if the same gene had different functions in two species, this would challenge research using animals to understand human genetics. Liao and Zhang (2008) found 1450 orthologous genes between mice and humans, and then concentrated upon 120 human genes. Genes were rated as essential ("loss of function renders the fitness of the organism zero") or non-essential. In practice, "essential" means the organism dies before puberty, or if survives into adulthood is infertile. Twenty-seven (22.5%) of the human genes rated as essential in humans were non-essential in the mouse. This study focused upon genes for diseases. So it could be that results from animal studies are not applicable to humans because many of the apparent anomalies in animal experiments merely reflect the unique biology of the species being studied (Barnard and Kaufman 1997). In another example, a vaccine for Alzheimer's disease ("AN-1972") worked on genetically modified mice, but there was evidence of brain inflammation in human clinical trials (Roundabout 2002). 2. The ethical and moral question of whether it is right to use non-human animals in this way, particularly when pain and suffering are involved. This issue is addressed by legal restrictions on the use of animals in experiments, like the Animals (Scientific Procedures) Act 1986 in Britain. Any experiment using a non-human animal requires a licence from the Home Office. Methods and Issues of Studying the Brain in Psychology; Kevin Brewer; 2009 ISBN: 978-1-904542-48-3

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In a report for the British Union for the Abolition of Vivisection (BUAV), Langley (2006) listed the types of experiments used with primates for "fundamental research". This is "knowledge-driven studies with no foreseen medical relevance, to basic medical research that might, in time, contribute to new ways of preventing or treating human disease" (p84). This included brain lesions, electrodes and probes to study vision, taste, hearing and the brain of marmosets and macaques. The reality of these experiments is suffering for the animals (box 2).

Vision research and similar studies on primates invariably cause suffering, sometimes classed as substantial. For electrophysiology, surgery typically, involves removing an area of skull to expose the brain, and cementing a metal ring over the area. To the ring is attached an electrode positioner and electrodes. Metal tubes are cemented onto the skull for restraining the monkey by the head during recording and stimulating sessions. Scleral search coils may be implanted in the eye to monitor eye movements. Animals are sometimes deprived of food or water for many hours prior to the experiments, to motivate them to perform visual tasks. During recording or stimulating sessions, which can last for several hours a day, animals are usually conscious and restrained in chairs by the metal fixtures cemented to the skull. To avoid other animals tampering with the implants, in some laboratories monkeys are kept in solitary confinement for the duration of experiments which can last for months or years. Some monkeys are used and re-used in similar experiments for very long periods of time. In the late 1980s, a monkey used at Oxford University in taste research had had electrode implants in the brain for five years, during which four experiments were conducted. At the Catholic University of Leuven in Belgium, some monkeys had been kept instrumented in single caging for two years, while being used and re-used in vision research. In tract-tracing studies, monkeys are injected with tracers into the eye, or elsewhere along the visual pathways. They are later killed for post-mortem analysis. Sometimes specific areas of the brain are ablated, or fibrous tracts severed, to discover the roles of these areas in vision (Langley 2006 p86).

Box 2 - Examples of the reality of suffering of experiments on vision, hearing and taste with primates. Concern generally over experiments with non-human animals has led to the "Three Rs" campaign to Replace, Reduce and Refine such experiments (Langley et al 2007). For example, the replacement of animal lesioning experiments, where an area of the brain is surgically damaged, by Transcranial Magnetic Stimulation (TMS) with human volunteers, where a magnetic field temporarily and safely disrupts part of the brain (table 10). Methods and Issues of Studying the Brain in Psychology; Kevin Brewer; 2009 ISBN: 978-1-904542-48-3

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STRENGTHS






Non-invasive. Temporary "virtual lesion". Use of humans to study humans. Repeated measures design experiments possible (ie: same individuals tested with and without TMS). Avoids problems of brain surgery, including operation itself, side effects, and functional re-organisation of the brain afterwards.

WEAKNESSES



Not as precise as surgery in inhibiting certain areas of the brain. Only short-term: not able to show permanent and long-term effects of damage to particular areas of the brain.

Table 10 - Strengths and weaknesses of the use of TMS with humans as alternative to animal lesioning experiments. 3. There are differences between human and non-human animals in terms of the use of language, and the flexibility of humans to learn. "Lack of linguistic complexity.. restricts animals' ability to solve problems by the manipulation of symbols, to reflect on the past and future.." and "..it may be only a human being who monitors his own monitoring, seeing his behaviour as more or less efficiently goaldirected.." (Hinde 1987 p26).

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4. INTERVENTION TECHNIQUES These techniques involve interfering with the brain in some way either through destruction or artificial stimulation of a particular area. 4.1. DESTRUCTION OF BRAIN TISSUE Brain tissue in a particular region of the brain may be deliberately destroyed or damaged to see the effect upon the behaviour of the human or non-human animal. For ethical reasons, it is more often with non-human animals. There are different techniques used to destroy the brain tissue: i) Ablation This is the surgical removal of a small area of brain. This can be done as an experimental investigation as well as medical intervention for malfunctioning brain tissue or to alleviate the symptoms of a disorder like severe epilepsy. Blasdel (1992) reported work with a technique that involved surgically removing part of the skull of a monkey and replacing it with a glass window. An optical dye is injected in the brain and it responded by colour change to an electrical field (ie: brain activity). When applied to the visual cortex, it was possible to establish which cells responded to left or right eye stimuli. This technique is most effective when studying the surface of the brain (Eysenck and Flanagan 2001). Chemical ablation is also used in a technique known as excitotoxocity (Whatson 2004). Cells are, in effect, poisoned, and destroyed that way. ii) Lesion This involves cutting part of the brain. The procedure with a lesion is known as "-ectomy", and with removal, it is an "-otomy" (Whatson 2004). For example, historically, psychosurgery with individuals with mental illness has focused on the pre-frontal cortex, and tissue connecting the frontal lobes to other areas of the brain. Pre-frontal lobotomy removes the cutting tissue and pre-frontal leucotomy cuts it. Ablations and lesions had been performed with knives, lasers that burn away the tissue, more recently, Methods and Issues of Studying the Brain in Psychology; Kevin Brewer; 2009 ISBN: 978-1-904542-48-3

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or with a strong electric current that does the same. 4.1.1. Psychosurgery Modern psychosurgery was began by Egas Moniz in 1936 who developed the technique of prefrontal leucotomy. However, "history has not treated the man or his invention kindly. Scientists and lay people alike look back upon the age of psychosurgery with critical eyes, deploring the procedure that turned men and women into ‘mental invalids’ or ‘drooling zombies’" (Tierney 2000 p22). Moniz (birth name: Antonio Caetano de Abreu Freire) was a Portuguese neurologist born in 1874. His technique to cut part of the frontal lobes in order to "cure" mental illness was based on the (incorrect) assumption that pathological circuits in the brain has become fixed (causing the mental illness), and surgery would eliminate the consequent abnormal thinking (Tierney 2000). Psychosurgery had been tried in the late nineteenth century to treat neurological symptoms of syphilis. But this involved making holes in the skull to drain fluid from the brain which was causing the insanity. Or parts of the cortex were removed in schizophrenics to reduce aggression. Both techniques "were greeted with much criticism from the medical communities in Britain and and Europe" (Tierney 2000). Moniz's aim was to destroy connections between the prefrontal cortex and other brain regions. The early operations did this by injecting a small amount of "absolute alcohol" which killed cells, while the later operations used a "leucotome" 1. This was a specially designed cutting device (Tierney 2000). The first series of operations (Moniz 1936) included twenty individuals with anxiety, depression, and schizophrenia. The first patient (a 63 year-old woman) was pronounced "cured" of her paranoia and hallucinations two months after the operation. Of the twenty, Moniz rated seven as cured, seven as improved, and six unchanged after the operation. Tierney (2000) noted the criticisms of Moniz's report from today's point of view:



1

Inadequate follow-up times (eg: days or weeks only); Absence of a control group - Not standard practice in

Picture at http://www.medicine.manchester.ac.uk/images/museum/full/warlinghamparkleucotome.jpg.

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the 1930s; Superficial evaluation of patients (ie: no standardised testing of abilities); Subjective evaluation of patients performed by himself or "asylum physicians who were aware of the aims of the procedure" (p31). Blind assessment of patients also not standard procedure in 1930s; Ignoring negative changes in personality, emotions, and behaviour after the operation. Moniz felt that the "facts speak for themselves: These were hospital patients who were well studied and well followed. The recoveries have been maintained. I cannot believe that the recoveries can be explained upon simple coincidence. Prefrontal leucotomy is a simple operation, always safe, which may prove to be an effective surgical treatment in certain cases of mental disorder (Moniz 1937 p1385 quoted in Tierney 2000 p31).

The problem of the time was that the alternatives in terms of treatments for severe mental illness were limited to techniques like insulin coma and electroconvulsive shock. Anything that seemed to work would be well received. Prefrontal leucotomies were quickly popularised in many countries, and, especially in the USA, were promoted by Walter Freeman (eg: Freeman and Watts 1950). "Freeman’s energetic support for psychosurgery, the sheer number of operations he performed, and his development of the infamous transorbital lobotomy (in which frontal white matter was destroyed via an ice pick-like instrument pushed into the brain though the bone behind the eyeball) are legendary..." (Tierney 2000 p31). The attitude of the time towards mental illness can be seen: Freeman repeatedly argued, however, that the symptoms of mental illness were more distressing to the patients and their families than the symptoms incurred by the surgery, and he pointed out that even if patients were not completely cured, the surgery often made them easier to care for and able to live at home (Tierney 2000 p32).

Moniz began by cutting the brain areas, while subsequent method of lobotomies destroyed brain areas. For example, in the USA, less than 300 lobotomies were performed in 1945, but this increased to nearly 5000 in 1951 (total of 20 000 between 1945-51), and 10 000 Methods and Issues of Studying the Brain in Psychology; Kevin Brewer; 2009 ISBN: 978-1-904542-48-3

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individuals had some form of psychosurgery between 194254 in England and Wales (Tierney 2000). "Thus Moniz’s innovative, ‘audacious’ procedure prematurely shed its status as an experimental, very cautiously applied operation, and entered a period of indiscriminate use and unchecked expansion" (Tierney 2000 p33). As Moniz received the Nobel Prize in Physiology or Medicine in 1949 for his work, voices of dissent for psychosurgery were being raised. An article in the "New England Journal of Medicine" (Hoffman 1949) described the post-operative patients as, among other things, "dull, apathetic, listless, without drive or initiative.." (p233; quoted in Tierney 2000 p33). "In retrospect, it seems obvious that the blind, grossly imprecise techniques employed by lobotomists could only impair the intricate functioning of the human frontal lobes, creating additional emotional and behavioural impairments rather than curing the initial disease" (Tierney 2000 p33). The 1950s and 1960s saw the development of psychotropic drugs for mental illness, and psychosurgery declined in popularity, though it is still used today. The "idea that brain surgery may help the mentally ill has never completely died, but instead returned to its point of origin, becoming once again a technique used very sparingly on patients with severe, chronic, treatment-refractory disorders" (Tierney 2000 p34). 4.1.2. Brain Lesions - Example with Animals: Lashley (1931) Lashley was interested in the localisation of brain function (ie: different parts of the brain have different functions). He began critical of the view from the nineteenth century that "because the mind is a unit the brain must also act as a unit" (p245). This is the view that the brain works as a whole for each ability. Lashley studied rats using apparatus of the day like a choice of cardboard doors with visual patterns and rats learn which pattern represents food, and mazes. Then an area of cortex was damaged to see the effect on visual perception and memory. It was found that damage to small areas of the occipital (visual) cortex affected vision the same as destruction of the whole cortex. This showed that specific functions were localised to particular areas. In some cases, the rats' brains were damaged before learning the maze. These animals were slower to learn than healthy rats, and it did not matter which part of the cortex was destroyed: "The degree of retardation Methods and Issues of Studying the Brain in Psychology; Kevin Brewer; 2009 ISBN: 978-1-904542-48-3

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seems proportionate to the amount of tissue destroyed, irrespective of the locus of injury" (p249). For example, destruction of any 10% of the cortex produced over one hundred errors during learning, 20% over two hundred, and 80% over 1000 errors. There was a correlation of 0.84 between amount of cortex destroyed and number of errors during maze learning. If the rats learned the maze, and then underwent surgery, the memory loss was related again to extent of damage not location. So "every part of the cortex plays a part in learning and in retention" (p250). This has been called the equipotentiality or mass action of neural tissue. Lashley's work had shown the paradox of the brain that certain functions are clearly localised to particular brain areas, whereas other functions are not and involve the whole cortex. Lashley defended the use of rats in his experiments with the following arguments:


"simplicity of the animal's behaviour, its steadiness in activity under the motivation of hunger and its availability in large numbers" (p246);




their use "only as a means of outlining problems and gaining clues which must in every case be retested by experiments with primates and by comparison with clinical evidence" (p246);




"these lower animals seem to every human mental trait and the evolution of mammals has the fundamental organisation activity" (p246).

show the beginnings of I have come to doubt that introduced any changes in or mechanism of cerebral

iii) Suction This is the removal of an area of the brain by inserting a fine tube called a cannula and applying suction, and is known as aspiration (Whatson 2004). iv) Temporary or transient lesion Techniques like freezing with cold liquids deactivate particular areas of the brain or an anaesthetic can be used. These processes do not permanently damage the brain. For example, Keenan et al (2001) studied five patients undergoing the intracortoid amobarbital (WADA) Methods and Issues of Studying the Brain in Psychology; Kevin Brewer; 2009 ISBN: 978-1-904542-48-3

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test for evaluation for surgery to treat epilepsy. This test inactivates one cerebral hemisphere through anaesthesia. Five right-handed (left hemisphere languagedominant) patients were shown pictures of morphed faces (a combination of own face and a famous face) during the anaesthesia of one hemisphere. After recovery from the anaesthetic, the patients were asked between a picture of their won face and the famous face as to which was shown. All patients selected the "self" face after anaesthesia of the left hemisphere and four of them chose the famous face after anaesthesia of the right hemisphere. The key finding for the researchers was the role of the right hemisphere in self recognition. There are strengths and weaknesses to using these techniques which cause damage to study the brain (table 11). STRENGTHS 1. Researchers can control which particular areas of the brain to destroy. 2. Allows researchers to pinpoint particular areas of the brain to establish the function of that area. 3. Able to measure behaviour before and after the brain damage. 4. Allows for replication of experiments. 5. Advantages over case studies of naturally occurring brain damage which is uncontrollable and unique to the individuals involved. 6. It is possible to compare the behaviour of the normal and the abnormal brain. WEAKNESSES 1. Produces permanent brain damage in most cases. 2. The damaged brain is no longer a normal brain, and so the applicability of findings to the general population are open to question. 3. Ethics of such techniques with human or non-human animals. 4. Accuracy of destruction process - either damaging the wrong area or causing extra damage beyond the area of focus. This is particularly relevant in the past when techniques were not as sophisticated as today. 5. Side effects of the operation. 6. There is usually a time lag between the operation to destroy the brain tissue and the measurement of behaviour. Changes to the brain may occur during that time.

Table 11 - Strengths and weaknesses of the deliberate destruction of brain tissue for understanding the brain. Methods and Issues of Studying the Brain in Psychology; Kevin Brewer; 2009 ISBN: 978-1-904542-48-3

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4.2. SPLIT-BRAIN PATIENTS There are situations where the brain has been deliberately damaged for medical reasons, like with split-brain patients. The brain is divided into two hemispheres which are connected by two hundred million nerve fibres known as the corpus callosum (figure 3). Split-brain patients are a number of individuals who, for medical reasons, had the corpus callosum cut in an operation called a commissurotomy or callosotomy. Thus the two hemispheres become separate (ie: unable to communicate).

(Source: Gray's Anatomy of Human Body, 20th US ed, 1918; in public domain)

Figure 3 - Drawing of brain from above showing corpus callosum. In the late 1950s, three individuals (WJ, NG, and LB; Gazzaniga 1995) with very severe epilepsy had this operation, and it "virtually eliminated" the seizures. Methods and Issues of Studying the Brain in Psychology; Kevin Brewer; 2009 ISBN: 978-1-904542-48-3

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These individuals were studied, initially by Roger Sperry who was joined by Michael Gazzaniga (Hock 2002). The surgeons in California, Phillip Vogel and Joseph Borgen, performed nine operations between 1962 and 1968, and more operations have taken place in the USA, France and Australia since then (Trevarthan 1987). Gazzaniga (1967) reported tests on the patients. Different types of tests were developed to assess each hemisphere. 1. Visual test Individuals were asked to focus on a point in the middle of the screen, and information was flashed on one side (visual field), so that only one eye could see it. This is known as the stimulus lateralization technique. This was tried with a row of light bulbs. When those on the right side were flashed, the patient reported seeing them, but when on the left side, the patient claimed to see nothing. However, when asked to point at the light that flashed, the patient did equally well for both sides. What was happening? Information from the right side goes into the left hemisphere, which is also the area for speech, and so the patient could answer the question. Information from the left side goes into the right hemisphere without language, and thus the patient cannot answer. Normally information passes between the hemispheres, and so this is not a problem. In one variation of this test, the researchers flashed a picture of a nude woman among the other pictures. When presented to the right eye, the female patient "verbally identified the picture of a nude", but when presented to the left eye, "she said.. she saw nothing, but almost immediately a sly smile spread over her face and she began to chuckle.. Although the right hemisphere could not describe what it had seen, the sight nevertheless elicited an emotional response like the one evoked in the left hemisphere" (Gazzaniga 1967 p29). 2. Tactile test The apparatus consisted of a screen through which the individual could touch an object but not see it. When objects were touched by the right hand, the patient was able to name them. But when touched by the left hand, the patient could not name them. However, they were able to correctly pick it out from a choice of objects presented as pictures. Methods and Issues of Studying the Brain in Psychology; Kevin Brewer; 2009 ISBN: 978-1-904542-48-3

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3. Visual and tactile test A picture of an object was shown to one eye and the task was to feel for that object behind the screen. When a picture was presented to the left eye, patients denied seeing anything, but they could find the object with their left hand behind the screen. Furthermore, a picture of a cigarette, for example, could be shown to the left visual field, and the left hand could find a related object, like an ashtray, behind the screen. "Oddly enough.. even after their correct response, ad while they were holding the ashtray in their left hand, they were unable to name or describe the object or the picture of the cigarette" (Gazzaniga 1967 p26). 4. Auditory test This type of test showed that the right hemisphere could comprehend language even if there is no speech centre. Patients were asked to reach into a bag of objects with their left hand and find a particular thing, which they could do. The could also find objects described like "the fruit monkeys like best". But Gazzaniga (1998) has admitted that the original patients were unusual, and the right hemisphere may not be able to comprehend language at all. 5. Drawing test The patients were asked to copy a simple drawing, like a cube, which could only be seen by one side of the visual field. Drawings presented to the left eye and drawn by the left hand were more accurate. This is because the right hemisphere is better at spatial relationships. Gazzaniga (1985) has argued that the brain is really two brains because of the specialisation in ability in each hemisphere. Levy (1985), among others, has challenged this idea: "Normal people have not half a brain, nor two brains, but one gloriously differentiated brain, with each hemisphere contributing its specialised abilities" (p44). There are very rare cases of children born without a corpus callosum, and it was found that information was being transmitted between the hemispheres (Hommet and Billard 1998). Gazzinaga (1998) reported a case that seemed to suggest that communication between the hemispheres was happening in split-brain patients. For example, when the Methods and Issues of Studying the Brain in Psychology; Kevin Brewer; 2009 ISBN: 978-1-904542-48-3

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word "bow" was flashed to one eye, and "arrow" to the other, the patient produced a bow and arrow drawings. But "we finally determined that integration had actually taken place on the paper, not in the brain". A patient shown the word "sky" in one eye and "scraper" in the other produced a drawing of the sky above a scraper, and not a skyscraper which would have been integration as in the normal brain. However, the word "fire" followed by "arm", for example, presented to the left eye produced a drawing of a rifle from the patient. Thus each hemisphere is capable of integrating information itself. The study of split-brain patients has strengths and weaknesses for understanding the brain (table 12). STRENGTHS 1. Possible to study rare cases and unusual events to understand more about the normal brain. 2. It has led to increased knowledge about the different functions of each hemisphere and brain lateralisation. 3. The knowledge of the location of different abilities has aided in treating individuals with injury to particular brain areas (Hock 2002). 4. Well documented cases studied over many years. 5. Split-brains in humans have shown that the human brain is different non-humans. Split-brains in monkeys, for example, still show communicate between the hemispheres. 6. The original patients have been studied in many different ways over the years, and testing different hypotheses about the brain.

WEAKNESSES 1. There are only a small number of such case studies. 2. The brains of these patients are abnormal because of the operation, which means they are not necessarily comparable to the normal brain. 3. It is not clear how much the epileptic seizures had damaged the brain before the operation. 4. The brain has changed post-operation. For example, a few patients developed speech in both hemispheres (Gazzaniga 1995). 5. Details of the original cases are not as well documented as modern cases where neuroimaging can establish the exact damage. 6. The idea of two separate brains in one head has been challenged.

Table 12 - Strengths and weaknesses of studying splitbrain patients to understand the brain. Methods and Issues of Studying the Brain in Psychology; Kevin Brewer; 2009 ISBN: 978-1-904542-48-3

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4.3. ARTIFICIAL STIMULATION This method involves stimulating the brain in some way to see the effect. It is usually chemical or electrical. Table 13 lists the strengths and weaknesses.

STRENGTHS

WEAKNESSES

1. The researcher is able to see the exact effect of controlled stimulation.

1. Most studies involve small samples which makes it difficult to prove that the precise effect is the same for all.

2. It can be used with human and non-human animals. 3. Researchers are able to make baseline measures before the process begins which is not possible with naturally occurring changes. 4. Chemical stimulation is a good way to study the biochemistry of the brain. 5. It is possible to use with humans when the brain is operated upon for medical reasons.

2. Stimulation, particularly with drugs, can have more than one effect. Thus it is difficult to interpret the results. 3. Invasive. 4. Some processes can be irreversible. 5. The implanting of microelectrodes in the brain changes the brain (ie: it is no longer a "natural" brain).

Table 13 - Strengths and weaknesses of artificial stimulation of the brain. i) Chemical stimulation The biochemistry of the brain can be altered by chemical substances to see the effects. Chemicals can be ingested (eaten or drunk) or injected. Micro-injections use thin needles that can inject minute quantities of chemicals into precise areas of the brain through an opening in the skull. The technique of microiontophoresis (using micro-pipettes) can even influence individual neurons (Whatson 2004). Chemical substances can either mimic biochemical processes (agonist drugs) or block the activity (antagonist drugs). For example, Harris et al (2005) were interested in the role of a neurotransmitter (orexin) in the lateral hypothalamus in reward-seeking behaviours. Male rats were conditioned to associate one chamber of two with a reward (food, cocaine, or morphine). Injection of an orexin antagonist reduced the preference for the rewarding chamber. Thus it was concluded that orexin must play a role in the brain in reward-seeking behaviour. While learning and memory can be studied by blocking Methods and Issues of Studying the Brain in Psychology; Kevin Brewer; 2009 ISBN: 978-1-904542-48-3

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the consolidation of memory in mice with a drug that inhibits protein synthesis, for example. Mice can learn the maze, but three hours later have no recall of the correct path (Murphy and Naish 2004). ii) Direct electrical cortical stimulation (DECS) This technique uses micro-electrodes to stimulate the surface of the brain. 4.3.1. Wilder Penfield During operations on the brain (between 1920s-50s), Wilder Penfield (figure B appendix) stimulated the surface of the exposed brain of individual undergoing brain surgery for epilepsy with a weak electric current (box 3). Patients, who were conscious during the operation, reported vivid memories and perceptions: There is an area of the surface of the human brain where local electrical stimulation can call back a sequence of past experience... It is as though a wire recorder, or a strip of cinematographic film with sound track, had been set in motion within the brain. The sights and sounds, and the thoughts, of a former day pass through the man's mind again (Penfield 1959 p1719).

Sterilization of scalp: local injection of nupercaine in solutions of 1 : 1,500 and 1 : 4,000 to which adrenalin is added. The sterile towels are then arranged perpendicularly so that the patient is cool, can see and move freely, and can be observed constantly. The role of anaesthetist is most important even though a general anaesthetic is rarely given, and in all of the records found in this communication we are indebted to our anaesthetist, Miss Mary Roach, who constantly followed the behaviour and movements of the patients as well as their blood-pressure, pulse and general condition through the long and sometimes trying ordeal of electrical exploration of the cerebral cortex. Osteoplastic craniotomy is used to expose large areas of the hemisphere, and the bone is replaced at the close of operation. The exposed brain is kept warm by the heat of lights focussed upon it, and moistened with Ringer's solution applied with an atomizer. Stimulation is carried out by either unipolar or bipolar platinum electrodeswhich emerge from a glass handle and are attached to insulated wires, all of which may be autoclaved (Penfield and Boldrey 1937 pp396-397).

Box 3 - Details of operation techniques as used by Penfield in 1930s. "Gentle electrical stimulation" of the temporal lobe Methods and Issues of Studying the Brain in Psychology; Kevin Brewer; 2009 ISBN: 978-1-904542-48-3

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in conscious patients produced sudden, powerful experiences which stopped when the electrode was removed. "The conclusion is unavoidable that the music a patient hears or the appearance before him of his mother or friend are memories. It seems evident that in some way the stimulating electrode is activating acquired patterns of neuronal connexion which are involved in the mechanism of memory. The patient considers and thinks over these hallucinations as he would a memory which he had himself summoned" (Penfield 1947 p343). Table 14 gives some examples of individual patients. In most cases, stimulation of the same area produced the same experience "provided the interval between stimulations is not too short or not too long" (Penfield and Perot 1963 p682), but sometimes unconnected experiences were reported from stimulation of the same spot.

PATIENT

RESPONSE TO STIMULATION

S.Be

"There was a piano over there and someone playing. I could hear the song you know". When the approximately same point was stimulated, he said, "Someone speaking to another, and he mentioned a name but I could not understand it.. It was like a dream". The same point was stimulated again, he said, "Yes, 'Oh Marie, Oh Marie'. Someone is singing it", and again on the fourth time (Penfield 1959).

D.F

Heard music, and "believed that a gramaphone (sic) was being turned on in the operating room" (Penfield 1959).

R.W

Heard mother talking on telephone when right temporal cortex stimulated - "My mother is telling my brother he has got his coat on backwards. I can just hear them" (Penfield 1959).

R.R

Stimulation of areas of the left temporal lobe produced recall of conversations in Johannesburg (Penfield and Perot 1963).

N.C

An orchestra playing some music which she could not identify. She asked for the same point to be stimulated until she recognised the piece of music. "The electrode was clearly activating a neuronal record which she could not activate herself by any voluntary effort" (Penfield and Perot 1963 p681).

Table 14 - Examples of reports by patients when areas of cortex stimulated with electrodes. The responses of the patients were not made up, as with shown with "S.Be": "The surgeon then warned him that he was about to apply the electrode again. Then, after a pause, the surgeon said 'Now', but he did not stimulate. (The patient has no means of knowing when the electrode is applied, unless he is told, since the cortex itself is Methods and Issues of Studying the Brain in Psychology; Kevin Brewer; 2009 ISBN: 978-1-904542-48-3

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without sensation). The patient replied promptly, 'Nothing'" (Penfield 1959 p1720). One patient, "J.V", reported the experience lasting after the stimulation had stopped. The experience of voices shouting lasted for fourteen seconds beyond the two-second stimulation. While sometimes the experience could disappear before the end of the stimulation (Penfield and Perot 1963). Penfield and Perot (1963) admitted that: All of these patients were subject to temporal lobe epilepsy which did, no doubt, make response from the cortex easier to elicit. This is to be expected since localised epileptic discharge renders the motor cortex of man more easily stimulable, and sensory cortex as well. This increase in stimulability (decrease in threshold) does not mean that the epileptic process is responsible for the nature of the response (p683).

But only 7.7% of patients reported such experiences during the operations (Eysenck and Flanagan 2001). Penfield was also able to map the motor cortex by showing that stimulation to a particular area produced movement of part of the body (Lyon and McLannahan 2004). Penfield and Boldry (1937), in particular, "confirmed the precise tomography of cortical localisation, and were able to relate stimulation of a discrete part of the brain with motor and sensory phenomena affecting a particular part of the body" (Schott 1993 p329). iii) Deep brain stimulation This involves placing micro-electrodes inside the brain. In the 1950s, a technique called electrical stimulation of the brain was tried with animals (Olds and Milner 1954) and humans (Heath 1954) by placing electrodes in the limbic system. Figure 4 is a photograph of the type of electrode used. The point is placed into the brain, and the top end is attached to an electrical current. Jose Delgado (1969) implanted electrodes, which were radio-controlled, in the brains of cats, monkeys and apes, bulls, and humans. He called the implants "stimoceivers". His most famous experiment from 1963 involved stopping a bull charging at him by stimulating its caudate nucleus (part of basal ganglia) in a bull-ring in Methods and Issues of Studying the Brain in Psychology; Kevin Brewer; 2009 ISBN: 978-1-904542-48-3

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(Source: Open Research)

Figure 4 - Deep brain stimulation electrode. Spain 2. Thankfully it worked to great public acclaim. However, "critics contended that the stimulation did not quell the bull's aggressive instinct, as Delgado suggested, but rather forced it to turn to the left" (Horgan 2005 p70). Twenty-five humans had electrodes implanted by Delgado between the 1950s and 1970s at a mental hospital in Rhode Island, USA. Stimulation of areas of the motor cortex produced physical reactions, like clenching of the fist, that could not be resisted by the patient. Not surprisingly, such work (nicknamed "brain chips") was controversial. Though brain implants are used today with many individuals suffering from Parkinson's disease (over 30 000 people)(Horgan 2005) 3. Carlson (1986) noted that "electrical brain stimulation is probably as natural as attaching ropes to the arms of the members of an orchestra, and then shaking all the ropes simultaneously to see what they can play.. the surprising finding is that stimulation so often does produce orderly change in the brain" (Carlson 1986).

2 3

Photographs from original experiment at http://www.biotele.com/Delgado.htm. This has led to modern developments in brain-computer interfaces (BCI)(Ohl and Scheich 2007).

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iv) Trans-cranial magnetic stimulation (TMS) Trans-cranial electrical stimulation (TES)(Merton and Morton 1980) was the forerunner of TMS, but the use of electrical stimulation on the scalp was painful. TMS works indirectly, so that it does not stimulate the scalp and produce pain (Hallett 2000). TMS (Barker et al 1985) involves placing a magnetic coil above the scalp (with a focused pulse of magnetixm; Whatson 2004) which produces electrical currents in the neurons in the underlying cortex. This stimulates or inhibits that area of the brain in a way that is noninvasive and reversible. Amassian et al (1989) was one of the first studies to use TMS to study perception. Participants were shown letters briefly on a computer screen, and TMS was delivered to the occipital cortex 80-100ms after. The participants reported seeing a blur or nothing at all. Developing upon this finding, Beckers and Zeki (1995) applied TMS to area V5 of the visual cortex, and this interfered with motion perception. Applying TMS while the brain is scanned allows researchers to "see" the neural changes (Allen et al 2007). Though the changes to the brain are reversible, there are concerns over the effects of TMS. Short durations of TMS can produce effects lasting hours and even days (Allen et al 2007). For example, short TMS pulses of less than one minute were found to suppress neural activity for 5-10 minutes in cats (Allen et al 2007). TMS has been developed and expanded in different ways (Huang et al 2009), like:


Theta burst stimulation (TBS) - Either continuous (cTBS) or intermittent (iTBS), which uses 50Hz bursts every 200ms to disrupt activities in the cells;




Controllable pulse shape TMS (cTMS) - Greater control over the strength of the electrical field generated.

Knoch et al (2006) applied low-frequency repetitive TMS (rTMS) for fifteen minutes to areas of the dorsolateral prefrontal cortex (DLPFC) while participants played the Ultimatum Game. This game is used to test fairness and co-operation. A proposer has a certain amount of money, and offers to share it with the responder. The proposer can offer any amount of money. If the responder rejects the offer, both players receive nothing, but if they accept, the money is divided Methods and Issues of Studying the Brain in Psychology; Kevin Brewer; 2009 ISBN: 978-1-904542-48-3

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accordingly. Many responders reject offers if they are not perceived as fair (eg: below 25% of available money). This goes against economic self interest which would accept any offer as better than zero. Acceptance rates for unfair offers in this experiment were 10% at baseline. With right DLPFC TMS this increased to 45%, but not with left side TMS. TMS "switched off" the area of the brain, and the participants were less able to resist the "economic temptation" of the offers. The DLPFC (right side, in particular) seems to be involved in over-riding "selfish impulses". However, the participants still knew the offer was unfair even with TMS and accepting it. 4.3.2. Studying Temporal Aspects of Perception Researchers studying the brain tend to use a combination of methods, and use newer techniques to confirm and develop findings from other methods. This is the case with TMS studies and visual perception. Visual perception involves a number of processes and aspects that have been studied (Battelli et al 2008):




"Primary features" - The "physics" of the visual stimulus (eg: light wavelength); Spatial components - The parts of the stimulus in relation to each other, and the stimulus in space; Semantic components - The meanings attached to the stimulus (eg: predator approaching) and thus the action required.

Take the example of a stimulus approaching. Details of the shape and motion are the primary features that reach the eye, and the spatial aspects relate to the direction. The semantic aspect is the fact that the stimulus is a charging bull. Battelli et al (2008) added another aspect of visual perception - a temporal component. This is the brain registering the time involved in the sequence of events, their duration, and the interval between events in order to co-ordinate action. As the bull approaches, the visual information has to be ordered into a correct sequence to show that the bull is moving towards the viewer before action is taken. Without a temporal sequencing of events it would be difficult to tell if the bull was running towards or away from the viewer. The time involved may be milliseconds, but time is being processed as part of the visual information. "The role of time at this scale is not so much to underpin the experience of time but to establish the ordering and nature of the flow of events" (Battelli et al 2008 p120). Methods and Issues of Studying the Brain in Psychology; Kevin Brewer; 2009 ISBN: 978-1-904542-48-3

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The time aspect of visual perception includes marking the arrival and the disappearance of of a stimulus in the visual field (opening and closing transients; Battelli et al 2008). The intervening period between them is the duration of the stimulus's presence. If the arrival is not marked, the stimulus will not be seen. While if the disappearance is not marked, another stimulus may be perceived as part of the original stimulus in motion. For example, two lights close together flashing on and off consecutively appear to be one light moving. Using the rapid serial visual presentation paradigm (RSVP), two letters are presented very quickly one after the other at the same point on the computer screen. If the time between them is faster than 400ms, the second letter is not seen. This has been called the attentional blink (AB) phenomenon (Battelli et al 2008). The temporal aspect of perception involves particular parts of the brain together called the "when" pathway, which goes with the "where" pathway (establishing the position of the stimulus in space and motion; "dorsal stream" involving inferior parietal lobe) and the "what" pathway (establishing what the stimulus is - form and face recognition; "ventral stream" involving inferior temporal lobe)(Cacioppo et al 2008). Because the processing of information is so quick, the experience of visual perception is a combination ofthese pathways. We just "know" the stimulus is a bull charging at us. Work with non-human primates (eg: Saalmann et al 2007) has shown that the lateral intraparietal cortex (LIP) is involved in the "when" pathway. Isolating the temporal aspect of perception occurs when there is damage to the brain which produces deficits in visual perception. In humans this means waiting for naturally occurring brain injuries to occur. That is until the development of TMS which is able to produce transient "damage" to the brain. Both observations from brain injuries (eg: Battelli et al 2003) and TMS studies (eg: VanRullen et al 2008; box 4) have confirmed that the right parietal cortex (figure 5) is involved in temporal processing in perception. The "when" pathway has been expanded to the "extended when" pathway to include anticipation of when an event will occur, and estimation of the duration of the period from one event to the predicted next time. This is "when-past", "how long", and "when-future" (Battelli et al 2008). TMS studies have shown that other areas of cortex are involved in the "extended when" pathway. This pathway also includes other senses than vision. Battelli et al (2008) proposed that "each sensory Methods and Issues of Studying the Brain in Psychology; Kevin Brewer; 2009 ISBN: 978-1-904542-48-3

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system will have its own 'when' pathway originating in sensory cortex and taking a route through the parietal and motor related cortices" (p124). In understanding the "when" pathway in perception, TMS studies are being used to confirm and develop findings from intervention studies with non-human primates, case studies of brain injured human patients, and EEG studies (eg: VanRullen et al 2006)

(Source: Joint effort on English Wikipedia; last part: King of Hearts; in public domain)

Figure 5 - Brain showing different lobes.

VanRullen et al (2008) used TMS while participants viewed the "continuous Wagon Wheel illusion" (c-WWI). This illusion is where a wagon wheel appears to rotate in the opposite direction to is actual rotation. The researchers explained the illusion in relation to the "when" pathway failing to sequence the temporal aspects of perception correctly. Disruption of the right parietal lobe with TMS weakened the illusion.

Box 4 - VanRullen et al (2008).

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5. STUDYING NATURALLY OCCURRING BRAIN DAMAGE The aim here is to study naturally occurring brain damage in order to gain clues about the healthy brain. There is no manipulation of the brain by the researcher, simply the study after the event. Acquired brain injury is generally through injury (eg: closed head injury) or illness (eg: stroke), and is studied by the case study method. 5.1. BRAIN INJURY/DAMAGE FROM BIRTH Most research studies individuals, usually adults, who suffer brain injury, but there are rare conditions where the individual is born with brain abnormalities. One such condition is "agenesis of the corpus callosum" (ACC) where the corpus callosum is partially or completely absent (Aribandi 2008). It is due to a genetic fault which hinders the normal brain development in the first trimester of gestation. ACC is usually associated with other central nervous system anomalies (85% of cases). This does effect the usefulness of studying such cases (table 15). Overall the condition is relatively rare (eg: 0.7 - 5.3% in the USA; Aribandi 2008), but more common in males.

STRENGTHS

WEAKNESSES

1. Possible to follow the development of individuals with such brain abnormalities.

1. Usually have multiple areas of brain abnormality which limits the comparison of single area damage to healthy controls.

2. Does not involve any intervention to cause brain abnormality. 3. Modern scanning techniques give details of the brain area damaged.

2. Many individuals do not live very long, even to adolescence. 3. Problems of studying such infants.

Table 15 - Strengths and weaknesses of studying naturally occurring brain injury from birth. 5.2. ACQUIRED BRAIN INJURY/DAMAGE These are cases where individuals have acquired brain damage later in life through injury (eg: Phineas Gage) or illness.

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5.2.1. Phineas Gage One of the best known case studies of brain injury is that of 25-year-old Phineas Gage (Harlow 1848) 4. He was a US railroad building foreman who suffered the freak accident of a three-foot long tamping iron being propelled through his skull by an explosion (figure 6). The iron entered the left cheek and exited the back of the skull causing damage to the left pre-frontal cortex. "Beyond the astonishing fact of Mr.Gage's survival was the description of his ability to walk immediately after the event, communicate sensibly, and remain lucid through most of the period following the injury" (Neylan 1999).

(Source: Harlow 1868; copyright expired; in public domain)

Figure 6 - Drawing of tamping iron through Gage's skull. John Harlow was the local doctor, and was called to help Gage about two hours after the accident: "He seemed to be perfectly conscious, but was getting exhausted from the haemorrhage, which was very profuse both externally and internally.." (Harlow 1848). The accident happened at 4.30pm on Wednesday 13th September (1848) near Cavendish, Vermont, and for the following month Gage slept a lot and has problems with the would healing, typical of the time and medical knowledge. On 11th October, Harlow (1848) wrote: "Intellectual faculties brightening.. Relates the manner in which it {accident} occurred, and how he came to the

4

Details were also reported in Bigelow (1850a and 1850b), Harlow (1849, 1868, 1869), and Anonymous (1851). Methods and Issues of Studying the Brain in Psychology; Kevin Brewer; 2009 ISBN: 978-1-904542-48-3

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house.. says he knows more than half of those who inquired after him. Does not estimate size or money accurately, though he has memory as perfect as ever." He returned home to his family at the end of November. Before the accident, he was described as having "temperate habits, and possessed of considerable energy of character" (Harlow 1848). Full details of the case were reported in Harlow (1868), and the focus was upon the change in the personality of Gage: His contractors, who regarded him as the most efficient and capable foreman in their employment previous to his injury, considered the change in his mind so marked that they could not give him his place again. He is fitful, irreverent, indulging at times in the greatest profanity (which was not previously his custom), manifesting but little deference for his fellows, impatient of restraint or advice when it conflicts with his desires, at times pertinaciously obstinate, yet capricious and vacillating, devising many plans of future operation, which are no sooner arranged than they are abandoned in turn for others appearing more feasible (Harlow 1848 quoted in Neylan 1999 p280).

Overall he was described as "no longer Gage" by friends and colleagues. He was forced to leave his job and wandered around for much of the rest of his life including a spell in Chile and ended up in San Francisco (where he died). Ferrier (1878) was the first to argue that the damage caused by the iron rod missed the motor and language centres of the brain, behaviours which were unaffected, but the damage to the left pre-frontal cortex caused the "mental degradation". Gage died twelve years after the accident. No postmortem study of the brain took place as Harlow only learned of Gage's death five years after it occurred (Damasio et al 1994), but the skull was later recovered. Measurements from the skull have been made to try and establish the exact brain damage. Subsequent studies have suggested damage to the right pre-frontal cortex as well as the left. Damasio et al (1994) believed that the behaviour changes shown by Gage were typical of general damage to areas of the whole pre-frontal cortex, and seen in recent cases of pre-frontal cortex injury: "Their ability to make rational decisions in personal and social matters is invariably compromised and so is their processing of emotion. On the contrary, their ability to tackle the logic of an abstract problem, to perform calculations, and to call up appropriate knowledge and attend to it remains intact.." (p1104). Methods and Issues of Studying the Brain in Psychology; Kevin Brewer; 2009 ISBN: 978-1-904542-48-3

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The case study of Phineas Gage has a number of strengths and weaknesses for understanding the brain (table 16). STRENGTHS 1. Detailed notes about Gage immediately after the accident from Dr.Harlow. 2. Insight and detail of an outstanding and rare case. 3. Possible to study brain damage that cannot be produced by an experiment with human participants. 4. Exceptional cases like this encourage research to discover more. 5. Freak accidents like this can highlight aspects of the brain not considered at the time (eg: frontal cortex and self control). 6. It is the nearest to "turning off" part of the brain to see the effect. 7. There are not ethical or moral issues as with experiments on nonhuman animals or humans. 8. Case studies produce rich, qualitative data. WEAKNESSES 1. No post-mortem study of the brain, so the exact area of damage is not known. 2. Because case studies like this depend upon accidents, there are few details and measures from before the event. Experiments are able to gain measures before and after the event. 3. Dependent upon the records kept by witnesses of the time. Though Harlow was a doctor, his records are not as detailed as those of modern medicine. 4. It is not advisable to generalise the findings from unique cases. 5. The damage to the brain is haphazard, so it is not really like experimentally "turning off" part of the brain. 6. Experiments with non-human animals would allow researchers to control the variables and isolate the exact cause and effect relationship. 7. Researchers may become involved with the case, and thus their reports lack objectivity. 8. Case studies are often low on quantitative data, which are more objective.

Table 16 - Strengths and weaknesses of the case study of Phineas Gage for understanding the brain. Macmillan (2000) was interested in how the Gage case Methods and Issues of Studying the Brain in Psychology; Kevin Brewer; 2009 ISBN: 978-1-904542-48-3

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was reported in psychology and psychiatry textbooks. he estimated that details appeared in 60% of such textbooks published between 1983 and 1998, and, in many cases, with errors. The errors related to seven elements of the story:


Dimensions of the tamping iron.




Gage's work - reports included that he was a miner or building a road.




Circumstances of the accident.




Damage done to Gage's skull and brain.




His treatment and recovery - one report had Gage walking to the doctor's office with the tamping iron still through his skull, and another described him as living for twenty years with it still in his skull.




Changes in personality and behaviour (table 17) - in an extreme case, Gage "virtually became a psychopathic personality who lied and could not be trusted to honour his commitments" (Macmillan 2000 p54).




His life after the accident - for example, Harlow said nothing about Gage's drinking, but a few textbooks reported him as "frequently drunk".

PRE-ACCIDENT

POST-ACCIDENT











"temperate habits" (Harlow 1848) "possessing an iron will as well as an iron frame" (Harlow 1868) "well-balanced mind.. very energetic and persistent in executing all his plans of operation" (Harlow 1868)




"he was gross, profane, coarse, and vulgar, to such a degree that his society was intolerable to decent people" (Anonymous 1851) "The equilibrium or balance.. between his intellectual faculties and his animal propensities, seems to have been destroyed. He is fitful, irreverent.. manifesting but little deference for his fellows" (Harlow 1868)

Table 17 - Key details about Phineas Gage from primary sources (Macmillan 2000). 5.3. BRAIN INJURY/DAMAGE THROUGH ILLNESS Brain damage and injury can occur through illness, of which one of the most common is stroke. Blood flow to part of the brain is restricted and the area is Methods and Issues of Studying the Brain in Psychology; Kevin Brewer; 2009 ISBN: 978-1-904542-48-3

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consequently damaged. Stroke can lead to visual agnosia (an inability to recognise familiar objects) and prosopagnosia (an inability to recognise familiar faces). Aviezer et al (2007) reported the case of SE, a 52 year-old Israeli man who suffered a stroke in 2004. He was unable to visually recognise common objects and faces, though tactile and auditory recognition were unaffected. He also had problems with colour perception, and orientation (eg: difficulty describing how to get home). He was tested two months after the stroke. SE could match geometric shapes, and copy and name simple figures (eg: square). But for drawings of complex objects, he scored 26% correct recognition (eg: a mushroom mistaken for a parachute). Despite not being able to name the object, he was able to give information about the purpose of the object and copy it accurately from memory. This showed that the problem was not related to semantic memory. In another test, an object was named and SE had to point to the correct line drawing out of five. He had a success rate of 77%. In a test with Navon hierarchical letters (Navon 1977)(figure 7), he could not recognise the global letter even when pointed out, only the local letters.

EEEE E EEEE E EEEE

YYYY Y YYYY Y YYYY

Congruent

Incongruent

Figure 7 - Examples of Navon's hierarchical letters. In the congruent condition (same global and local letters), shown for 450ms, SE recognised the global letter in 61% of trials and 73.4% for the local letters. For the incongruent condition, the correct trials were 33% and 73.2% respectively. Aviezar et al tested for unconscious recognition of objects. SE was shown a drawing of an object (which he could not recognise) for 300ms, followed by a word. His task was to say as quickly as possible if the word was an animate or an inanimate object. Some preceding drawings were the same as the word, others were not. If he had unconscious recognition, his reaction time would be faster when the drawing was the same as the word. Methods and Issues of Studying the Brain in Psychology; Kevin Brewer; 2009 ISBN: 978-1-904542-48-3

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The reaction time for the "same" condition was 2076ms compared to 2328ms for the "different" condition. So it seemed that SE had unconscious recognition of objects, and the problem was the conscious recognition of them. This was confirmed when the last experiment was repeated using scrambled drawings. Here there was no difference in reaction times between the two conditions. Some improvements in visual recognition abilities were found when SE was tested nine months after the stroke. SE also suffered from prosopagnosia, and could not even recognise faces known before the stroke, including famous people, family members, and himself. Furthermore, when presented with faces with parts changed (eg: apples instead of eyes), he recognised the objects but not that the stimuli were faces: "here are some fruits (pointing to the eyes).. judging by their shape, they are apples.. and these (points to nose and mouth) might be branches.. and this here (points to circular outline of face) might be a plate". But occasionally, he did "see" the face in such a stimuli when pointed out to him. A problem with testing was that SE used semantic information, like context, to aid his recognition of objects. For example, when in an office, it was noticed that he recognised a stapler, a pen, and other expected objects, but not unexpected objects. This showed that his was using top-down information in visual perception. Aviezer et al tested this experimentally. The task was to say if a line drawing was a possible or an impossible object. Before each drawing, SE was shown a word for 1500ms. The word, known as the primer, was either for the same object or not in the following drawing. Where the word was the same as the possible object, SE was 82% accurate in naming the drawing (50 out of 61 trials), but when the word was different to the drawing, 50% accuracy (21 out of 42). For the drawings of impossible objects, he got 69% correct but took a long time (average 13.5 seconds). 5.3.1. Clive Wearing On 29th March 1985 Clive Wearing collapsed and was admitted to hospital with encephalitis (inflammation of the brain) caused by the herpes simplex 1 virus (which causes cold sores usually)(Wilson and Wearing 1995). In rare cases like this, the virus is dormant near the spinal column, "wakes up" and heads for the brain. The subsequent inflammation of the brain caused damage to the

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hippocampus, which is linked to memory 5. After hospital he showed many symptoms of confusion, not understanding speech, and repeating meaningless phrases. He went through a phase of backward spelling and talking. The world seemed to be continually changing for him as he could not retain information for longer than the briefest time. He showed epileptic and Parkinson's symptoms like jerking and shaking. Confabulation is also common. Clive is unable to lay down new memories, and has a limited number of memories from before the illness. He is in a permanent state of feeing that he has just woken up that minute (with a memory span of seconds) from "unconsciousness". He keeps a diary compulsively (which began on 7th July 1985): "7.46am: I wake for the first time. 7.47am: This illness has been like death till NOW. All senses work. 8.07am: I AM awake. 8.31am: Now I am really, completely awake. 9.06am: Now I am perfectly, overwhelmingly awake. 9.34am: Now I am superlatively, actually awake (Wearing 2005 quoted in France 2005) 6.

"Clive's world now consists of a moment with no past to anchor it and no future to look ahead to. It is a blinkered moment.. So it's a moment to moment consciousness as it were.. a time vacuum" (Deborah Wearing speaking on BBC documentary, "The Mind Machine", in 1988 quoted in Wilson and Wearing 1995 p15). Yet he remembers his wife, Deborah, but not his wedding nor his children's names (France 2005). There are some intriguing behaviours like learning the route to the hospital dining room and back to his room over seven years. Though he did need his name to be on his door. Also "After the first few years post-insult, when talking to his wife he began to abbreviate his questions [ "How long?" = "How long have I been ill?"; this suggests that, at some level, he is aware he must have asked them before" (Wilson and Wearing 1995 p27). Clive's semantic memory (general knowledge) is less affected, but its usefulness is limited because of the severe damage to the episodic memory (autobiographical

5

A MRI scan in 1991 showed damage in the temporal lobe, especially the left, including almost complete disappearance of the hippocampus (Wilson and Wearing 1995). 6 Clive reported auditory hallucinations in his diaries as a "master tape" ("what he thinks is a tape of himself playing in the distance"; Wilson and Wearing 1995). Methods and Issues of Studying the Brain in Psychology; Kevin Brewer; 2009 ISBN: 978-1-904542-48-3

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memories). His IQ was tested as 106 immediately after hospital, and estimated as 120-140 pre-illness (Wilson and Wearing 1995). Before the illness, he was an accomplished musician, and he still retains these ability - to sight-read music, to play the piano and organ, sing and conduct a choir (Sacks 2007). Barbara Wilson made the first formal assessment of his amnesia between November 1985 and May 1986 (Wilson and Wearing 1995) using different psychometric tests:


Rivermead Behavioural Memory Test (Wilson et al 1985) This involves twelve tasks related to everyday life (eg: remembering a person's first and last names; remembering an appointment)(Strauss et al 2006);




Wechsler Memory Scale (Wechsler 1945) - Recall of prose passage immediately and after delay;




Rey Osterreith Complex Figure Test (Osterreith 1944) The task is to copy a drawing of a complex figure from memory;




Autobiographical Memory Interview (AMI)(Kopelman et al 1989) - Recall on personal semantic questions (facts from own past life) and autobiographical incidents (specific incidents in own life);

Clive's performance on each test is detailed in table 18.

TEST

CLIVE'S PERFORMANCE

Rivermead Behavioural Memory Test

0/12

Wechsler Memory Scale

immediate recall - 1 delayed recall - 0 (and confabulation)

Rey Osterreith Test

No delayed recall

AMI

Abnormally poor

Table 18 - Clive Wearing's performance on memory tests in 1985-6. Clive was formally assessed in 1989, 1991 and 1992 by Wilson. The scores on the different memory tests were unchanged including an immediate recall of six digits (forward) and four backwards. His IQ seemed to have dropped to 97 (Wilson and Wearing 1995).

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Other tests used included the Graded Naming Test (GNT)(McKenna and Warrington 1983) which tests naming of thirty objects (eg: corkscrew, handcuffs) and thirty proper names (eg: Hitler, Shakespeare) 7, and a semantic memory test 8 (Hodges et al 1992) on which Clive was similar to a moderate Alzheimer's sufferer)(table 19).

Categories:

LIVING

NON-LIVING

Naming pictures (out of 24)

46

83

Naming to description (out of 12)

17

67

Word-picture matching (out of 24)

71

100

(After Wilson and Wearing 1995)

Table 19 - Percentage of total items correct on semantic memory test.

7

The logic behind this test was a case study of "GBL", who had stroke damage to the left hemisphere, and showed perfect naming of objects, but poor naming of famous people (McKenna and Warrington 1980). 8 This tests knowledge with tasks that involve naming pictures (eg: birds), naming items described, and matching words to pictures. Methods and Issues of Studying the Brain in Psychology; Kevin Brewer; 2009 ISBN: 978-1-904542-48-3

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6. RECORDING ELECTRICAL ACTIVITY 6.1. ELECTROENCEPHALOGRAM (EEG) This method records the general electrical activity of the brain by attaching electrodes to the scalp. The brain waves vary in frequency (the number of oscillations per second), and in amplitude (measured as half the height from the peak to the trough). One complete oscillation is a cycle, and cycles per second (cps) are measured. Hans Berger (1929) is seen as the first report of human EEG (figure 8).

(Source: Berger 1929; in pubic domain)

Figure 8 - First human EEG recording. EEG readings show four major types of brain waves:





Beta waves (13 cps or more) - recorded in adults awake and alert; Alpha waves (8-13 cps) - recorded in adults awake, but relaxed; Theta waves (4-7 cps) - mainly in young children; Delta waves (1-3 cps) - mainly in infants, and sleeping adults (Gross 1992).

Table 20 lists the advantages and disadvantages of EEG, and in relation to the other methods of recording electrical activity. 6.2. EVOKED POTENTIALS OR EVENT-RELATED POTENTIALS This is the measurement of small groups of cells, and is more sensitive than EEG. Recordings are made on the scalp and neck away from main EEG regions of spinal cord, brainstem and cortex. Measuring the response to a specific stimulus by groups of neurons is measuring event-related potentials.

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ADVANTAGES

DISADVANTAGES

1. Measures electrical activity of whole brain.

1. Measuring whole brain's electrical activity tells us little about specific area activity. This is overcome by using the other techniques of recording electrical activity.

2. Ability to measure whole hemisphere activity. 3. Easier to perform than single unit recording. 4. Non-invasive.

2. Only indirect measure of brain activity because electrodes on scalp. Invasive techniques of recording overcome this problem.

5. Both the waking and sleeping brain can be studied.

Table 20 - Advantages and disadvantages of EEG. 6.3. MAGNETOENCEPHALOGRAPHY (MEG) This technique makes use of changes in the magnetic fields in cortical neurons, which can be detected by magnets placed on the scalp. Liquid helium coiled superconducting sensors (eg: single superconducting quantum inference devices; SQUIDS) are used to pick up the faint magnetic fields. It is able to detect changes in signals over milliseconds, but it does not have the localised accuracy of MRI scans. "GY" is a man in his 50s who, due to a car accident as a child, has brain damage that limits his visual abilities. He is "functionally blind" on his right side, but can "guess" correctly stimuli shown in this visual field. This is known as "blindsight". He was tested using a whole-head MEG system "with 151 radial gradiometers over the head and 29 reference gradiometers and magnetometers for ambient field correction. Signals were digitised at a sampling rate of 1250Hz (0-200Hz bandwidth) during epochs lasting five seconds, beginning one second prior to stimulus onset" (Schurger et al 2008 pp2190-2191). The researchers were able to identify neural responses to awareness of a target and attention-withoutawareness of a target in the blind field. The neurons that fire are similar in both cases. 6.4. SINGLE UNIT RECORDING The activity of single neurons can be measured by invasive microelectrodes placed in the brain. This is different to other techniques for recording electrical activity which do not go inside the brain. The most famous use of this technique was by Hubel Methods and Issues of Studying the Brain in Psychology; Kevin Brewer; 2009 ISBN: 978-1-904542-48-3

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and Wiesel (eg: 1959, 1962) who mapped the visual cortex of a cat by recording visual activity in response to different visual stimuli. They found different cells in the cortex that responded to different line orientations. The cerebral cortex is highly developed in mammals, and may include over 100 000 neurons for each square millimetre. The primary visual cortex (or striate cortex) occupies the area at the back of the brain (occipital lobe). Hubel and Wiesel began their work in 1958, and the first set of results were published a year later. Further details were then reported in 1962. Alongside this work on single cell recording, Hubel and Wiesel studied the development of the visual system in kittens where one eye was surgically closed (Hubel and Wiesel 1998). In the single cell recording experiments, the cats were paralysed by anaesthetic, but remained conscious. The researchers used minute micro-electrodes to measure the electrical activity of individual brain cells at the back of the surface of the brain. Lines of different angles and orientations were shown on a screen in front of the cat's eyes. Painstakingly, the researchers measured the response of individual cells, and built up a picture of how cells in the visual cortex work. Hubel and Wiesel (1959) identified three types of cells in the visual cortex: i) "simple cells" - these cells respond to particular features of the line only (eg horizontal), and in particular locations of the visual field; ii) "complex cells" - these cells respond to particular orientations also, and receive information from the simple cells; iii) "hypercomplex cells" - these cells are also sensitive to the length of the line, and receive information from the complex cells. The information from each cell is processed in an upward direction (ie: from simple to hypercomplex). Working downwards through the cortex, the researchers found that the cells were stacked in "ocular dominance columns". In a more recent example, Romo et al (1999) recorded the activity of single neurons in the prefrontal cortex of four monkeys during a task to discriminate between two mechanical vibrations to the fingertips. Four hundred and ninety-three neurons were recorded by seven moveable microelectrodes. Methods and Issues of Studying the Brain in Psychology; Kevin Brewer; 2009 ISBN: 978-1-904542-48-3

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7. COMPUTER TOMOGRAPHY/NEUROIMAGING Brain scans can be used in a number of ways: i) To study the biochemistry in the brain. ii) For the measurement of cerebral blood flow or regional blood flow (rCBF) to particular areas of the cortex. For example, PET scans show a time lag of 1-3 seconds for blood flow rises after the start of activity in an area of the brain where there is low rCBF. iii) Closely linked to (ii) is the measurement of cerebral metabolism; eg: the rate of use of oxygen or accumulation of deoxyglucose shows the active parts of the brain in PET scans. It is possible now to study regional glucose metabolism (rCMRglu) in specific areas of the cortex, using, for example, 18 F-deoxyglucose (18-FDG). iv) To assess structural brain differences; eg: the reduction in certain brain areas in CAT scans. "With these new imaging techniques, researchers interested in the function of the human brain were presented with an unprecedented opportunity to examine the neurobiological correlates of human behaviours" (Raichle 2003 p3959). Cacioppo et al (2008) noted the impact of neuroimaging: "The detailed three-dimensional colour images provided by neuroimaging, modelling statistical properties of the working brain, have captured the imagination of the public and the science community, shaped funding priorities at federal funding agencies and foundations, and produced a dramatic growth in scientific papers and journals in the area" (p62). The popularity of studies using neuroimaging techniques can be seen in the number of papers recorded on PubMed 9 - nine using fMRI in 1993 to 2139 in 2007 (Poldrack and Wagner 2008). Neuroimaging has a number of advantages and disadvantages (table 21).

9

This is a database of medical and related academic research provided by the US Library of Medicine and the Nationa Institutes of Health (http://www.ncbi.nlm.nih.gov/pubmed/). Methods and Issues of Studying the Brain in Psychology; Kevin Brewer; 2009 ISBN: 978-1-904542-48-3

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ADVANTAGES

DISADVANTAGES

1. Detailed picture of the living brain.

1. Health risks with some techniques.

2. Pictures of the brain in 3-D.

2. Expensive to use.

3. Able to watch changing brain including blood flow patterns.

3. Scanners can be noisy and confined spaces to remain still in for long periods of time (eg: 3 hours for fMRI).

4. Able to detect damage to the brain. 5. Comparisons can be made between individuals or by looking at the same brain area in the same individuals at two different times. 6. Non-invasive. 7. Some techniques have no know health risks; eg: MRI (Berger 2002). 8. So much more information about the brain than other methods.

4. Require large computing capacity to convert raw data into visible images. 5. Some methods have time lags between brain activity and measurement; eg: fMRI measures blood flow approximately one second after neuronal activity (Raichle 1994). 6. Some techniques produce better quality images than others. 7. How to interpret the results. 8. Ethics of claims about such techniques.

Table 21 - Advantages and disadvantages of neuroimaging. There are a number of different neuroimaging techniques which show the structure or function of the brain (table 22):


Computerised axial tomography (CAT)




Positron emission tomography (PET)




Single-photon emission computed tomography (SPECT)




Magnetic resonance imaging (MRI)




Magnetic resonance spectroscopy (MRS)




Functional magnetic resonance imaging (fMRI)

Neuroimaging studies in recent years have both confirmed and challenged existing theories and ideas in psychology, and especially in cognitive psychology (table 23).

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TECHNIQUE

STRUCTURE OR FUNCTION

MAIN ADVANTAGE

MAIN DISADVANTAGE

CAT

S

Detect damage in brain

Health risks of Xrays

PET

F

Shows active brain

Health risk of radioactivity

SPECT

F

More sensitive than PET

Shows activity over 60-second period rather than moment by moment (Eysenck and Flanagan 2001)

MRI

S

Detailed picture of brain anatomy

Cannot show function

MRS

F

Shows brain's chemical compounds

Requires very low temperature to work (ie: 4 degrees above absolute zero)

fMRI

F

Shows localised brain activity

Need for patient to be perfectly still for long periods

Table 22 - Different techniques of neuroimaging.

EXISTING IDEA

FINDING FROM NEUROIMAGING STUDY

Short-term memory and long-term memory distinctively different

Challenged: Unitary model of memory (Nee et al 2008)

Declarative memory in hippocampus, but not nondeclarative memory

Confirmed: Knowlton and Foerde (2008)

Table 23 - Neuroimaging studies and existing ideas in cognitive psychology. 7.1. COMPUTERISED AXIAL TOMOGRAPHY (CAT SCANS) First used in 1972 (Sadock and Sadock 2003), this method produces a 3D X-ray picture of the static brain based on many X-rays from different angles and then combined together by the computer. X-ray machines are based on the principle that abnormal tissue absorbs X-rays to different degree to normal tissue. It is best at showing the presence of blood clots, tumours, and enlarged ventricles. There is a small risk from the X-rays if CAT scans are used too often on the same individuals. Owens et al (1985) performed a British study based on a sample of 112 hospitalised patients with schizophrenia. CAT scan results showed that lateral Methods and Issues of Studying the Brain in Psychology; Kevin Brewer; 2009 ISBN: 978-1-904542-48-3

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ventricular size increased more often in the patients than controls. In other words, the brain volume was reduced. The type of treatment was found to play no role either. These findings were constant over the length of the illness suggesting it was not a product of the disorder (Lewis 1996). This method has been supplanted by others, except for assessing calcification, which may be invisible on MRI (Sadock and Sadock 2003). 7.2. POSITRON EMISSION TOMOGRAPHY (PET SCANS) This technique is able to show the active brain by following the movement of a radioactive substance that has been injected into the brain (figure 9). Radioactivally labelled glucose molecules travel to active areas of the brain. When the radioactive atoms decay, they emit positrons (sub-atomic particles). These encounter electrons (the opposite type of particles) and both are annihilated. This gives rise to gamma rays that travel in opposite directions, and these can be traced to the point of origin. Its strength is the ability to show blood flow patterns in the brain, which can be affected by, for example, strokes. Different radioactive tracers (eg: water labelled with oxygen isotope 15O) can be used to target different aspects of the brain's activities, like blood flow, glucose metabolism, dopamine receptors, or MAO activity (Grasby et al 1996). Because a small amount of radioactivity is involved, the World Health Organisation recommends one PET Scan per five years. 10 PET scans or 2 SPECT scans are the same as annual background radiation exposure (Liddle 1996). Baxter et al (1992) performed a study based upon 18 patients with obsessive-compulsive disorder given either drug therapy or behaviour therapy. Initial PET Scans showed high levels of activity in the caudate nucleus in the right hemisphere when suffering an attack of the disorder. Thirteen of the patients responded to the treatment, and, in a second PET scan, the caudate nucleus was less active.

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(Source: US Department of Health and Human Services; in public domain; http://www.nia.nih.gov/Alzheimers/Resources/HighRes.htm)

Figure 9 - PET scan of healthy brain (top) and Alzheimer's disease brain (bottom). Raichle et al (1994) used PET scans to show that different parts of the brain are active during the process of learning. Participants were asked to generate a verb to go with a noun (eg: hammer). Forty nouns were presented at a rate of one every 1.5 seconds. This was the "naive" condition, and areas of the brain like the left prefrontal cortex and anterior cingulate cortex were active. Then the task was repeated ten more times with the same nouns. This was the "practised" condition, and participants produced stereotyped responses over time. Now there was less activity in the cortex areas than in Methods and Issues of Studying the Brain in Psychology; Kevin Brewer; 2009 ISBN: 978-1-904542-48-3

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the naive condition. In the third ("novel") condition, new nouns were introduced and the brain activity returned to the same as the naive condition. Brain activity is different for new and learned tasks. 7.2.1. Single-photon emission computed tomography (SPECT) This is a more sensitive measure of blood flow in the brain. It makes use of exametazime labelled with technetium isotope, 133mTc, for example (Liddle 1996). 7.2.2. Hippocampus and London Taxi Drivers Maguire et al (1997) used PET scans to study the hippocampus (figure 10) and spatial (or topographical) memory of eleven male London taxi drivers. All the men has passed the stringent examination of their recall of London streets (known as "The Knowledge") to become licensed. The participants were tested on different tasks (in each case twice):


Routes - describe the shortest route between a starting and a destination point in London (recall of topographical knowledge involving the sequencing of information);




Landmarks - describing the appearance of world-famous landmarks (not in London) that they had never visited (recall of topographical knowledge);




Film plots - recall the plot of a familiar film (seen five times or more)(recall involving sequencing of information);




Film frames - recalling individual frames from famous films;




Baseline - repeating two four digit numbers (control task).

Blood flow (rCBF) to areas of the brain was used as the measure of activity in response to a particular task. Each task showed a slightly different pattern of brain activation (table 24), but the routes task involved activation of the right hippocampus, in particular, compared to the baseline. Box 5 gives an example of a taxi driver's description of a route to take.

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(Source: Washington irving; in public domain)

Figure 10 - Hippocampi in human brain.

TASK

MAIN BRAIN AREAS ACTIVE

Route

Extrastriate regions; medial parietal lobe; posterior cingulate cortex; parahippocampal gyrus; right hippocampus

Landmarks

Posterior cingulate cortex; medial parietal lobe; occipito-temporal regions

Film plots

Left frontal regions; left middle temporal gyrus

Film frames

Left frontal regions; right middle temporal gyrus

Table 24 - Main areas of the brain activated by different tasks.

Task: Pick up on Grosvenor Square in Mayfair, drop off at Bank Underground Station, then at the OvalCricket Ground. "Grosvenor square, I’d leave that by Upper Grosvenor Street and turn left into Park Lane. I would eh enter Hyde Park Corner, a one-way system and turn second left into Constitution Hill. I’d enter Queen Victoria Memorial one-way system and eh leave by the Mall. Turn right Birdcage Walk, sorry right Horse Guards Parade, left Birdcage Walk, left forward Great George Street, forward into Parliament Square, forward Bridge Street. I would then go left into the eh the Victoria Embankment, forward the Victoria Embankment under the Blackfriars underpass and turn immediate left into Puddledock, right into Queen Victoria Street, left into Friday Street, right into Queen Victoria Street eh and drop the passenger at the Bank where I would then leave the Bank by Lombard Street, forward King William Street eh and forward London Bridge. I would cross the River Thames and London Bridge and go forward into Borough High Street. I would go down Borough High Street into Newington Causeway and then I would reach the Elephant and Castle where I would go around the one-way system” (Maguire et al 1997 p7106).

Box 5 - Example of taxi driver's description of route. Methods and Issues of Studying the Brain in Psychology; Kevin Brewer; 2009 ISBN: 978-1-904542-48-3

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Maguire et al (1997) showed that the hippocampus was more active in spatial memory tasks. Subsequently, MRI scans showed the structure of the hippocampus as different in London taxi drivers. Maguire et al (2000) compared sixteen experienced male taxi drivers with 50 healthy (non-taxi driving) controls. The taxi drivers had significantly different hippocampi (right and left) than the controls, though the overall volume was the same, and the brains showed no other differences. The difference was manifest as a larger posterior part and a smaller anterior part (table 25). Furthermore, length of time spent as a taxi driver correlated with right posterior hippocampus size. Overall, this work showed that "mental maps" are stored in the posterior hippocampus.

HIPPOCAMPUS

TAXI DRIVERS

NON-TAXI DRIVERS

Right - anterior - posterior

95 76

105 74

Left - anterior - posterior

80 75

100 70

(All significant differences p<0.05 between taxi and non-taxi drivers) (After Maguire et al 2000)

Table 25 - Size of areas of hippocampus (mm²). 7.3. NUCLEAR MAGNETIC RESONANCE IMAGING (NMRI or MRI) This technique, which entered clinical practice in 1982 (Sadock and Sadock 2003), also shows the static brain, through the use of magnetic fields (figure 11). It works by measuring the hydrogen atoms in water. The hydrogen nuclei are exposed to strong magnetic fields and line up like tiny magnets. Then they are hit with radio signals which causes them to move out of alignment. This produces a signal that can be measured. Compared with CAT scans, MRI provides a better contrast between grey and white matter. The upshot of which is more anatomical detail (Johnstone 1993). This is no need for radioactive substance to be injected, but there is concern about the effect of the strong magnetic field on the body. Manganese has been used recently to enhance brain activity in MRI scans (manganese enhanced MRI; MEMRI), though in large doses it is toxic (Silva and Bock 2008).

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(Source: NASA; in public domain; http://spaceresearch.nasa.gov/general_info/05feb_superconductor.html)

Figure 11 - MRI scan of brain from side. Johnstone et al (1989) had three groups of participants receive MRI scans: 21 individuals with schizophrenia, 20 with bipolar disorder, and 21 controls. The first group showed two brain structure differences compared to the others: larger temporal horns of the lateral ventricles, and a reduction in the left temporal lobe area. Thompson et al (2001) were able to produce 3D maps of the grey matter of the brain and the cortical surface using high-resolution 3D MRI of forty healthy Finnish adult twins. Identical twins were "almost perfectly correlated in their grey matter distribution". 7.4. MAGNETIC RESONANCE SPECTROSCOPY (MRS) MRS is based on the same principles as MRI, and uses magnetic fields - unpaired photons and neutrons aligned with a magnetic field. Radio frequency pulsing causes nuclei to absorb and emit energy. This produces a spectrum of the brain's chemical compounds. There are different types of MRS: for example, observing the proton nucleus (1H) in the hydrogen atom (H MRS), or the stable isotope of phosphorous (31P) (Frangou and Williams 1996). 7.5. FUNCTIONAL MAGNETIC RESONANCE IMAGING (fMRI) This technique detects tissue mass based on blood flow, by measuring changes in deoxyhaemoglobin when Methods and Issues of Studying the Brain in Psychology; Kevin Brewer; 2009 ISBN: 978-1-904542-48-3

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neurons are active. Increased neural activity means a reduction in the concentration of deoxyhaemoglobin. In practice, it is possible to localise neuronal activity. It measures the "pooled neural responses across a voxel (a three-dimensional volume element analogous to a pixel in a two-dimensional digital image) or many voxels that constitute a brain region" (Grill-Spector and Sayres 2008). Recent developments include fMRI-adaptation (fMRIA), pattern analysis (PA), and high-resolution fMRI (HfMRI)(Grill-Spector and Sayres 2008). There is no need for a radioactive tracer (Liddle 1996). But acquisition of enough images for study can require the participant's head to remain still in the machine for up to three hours. Small changes in head position can lead to "erroneous interpretations" of brain activation (Sadock and Sadock 2003). The strong magnetic field has also been shown to slow down brain processes, even if it is not harmful (Foucher et al 2008). Brain activity in a female partner of a couple was examined with fMRI for "pain empathy" as the male partner was seen to receive a painful electric shock to the hand. Certain areas (eg: rostral anterior cingulate cortex) were activated both when experiencing pain and when seeing partner experience pain. Seeing a loved one experience pain was not identical to experiencing pain, but there were common patterns of brain activity (Singer 2004). 7.6. ETHICAL ISSUES AND NEUROIMAGING The technology of neuroimaging has implications related to free will, agency, and personality among other things, and it requires an ethical awareness for their use by researchers. This ethical awareness has been called "neuroethics" (Marcus 2002). Fuchs (2006) distinguished two main areas of ethical concerns with neuroimaging: i) The "new methods and technologies, by laying bare neural correlates of personal identity, cause problems of individual rights on privacy, non-interference and inviolability" (p600); ii) The findings are reductionist in that everything is reduced to neurons firing and electrochemical processes. Methods and Issues of Studying the Brain in Psychology; Kevin Brewer; 2009 ISBN: 978-1-904542-48-3

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For example, Libet (1985) showed that electrical activity in the brain ("readiness potential") occurs 500ms before an individual consciously chooses to do an action. Individuals, wired to EEG sensors, were told to pick up items when they wanted. If free will is nothing more than this, than is an individual ever truly responsible for their behaviour? Responsibility So many of the findings using neuroimaging questions the responsibility of the individual for their behaviour. The assumption of biological determinism is implicit (and explicit) in the research. Adrian Raine (eg: Raine et al 1998), for example, using PET scans with convicted murderers, has found poor prefrontal cortex functioning compared to the general population. Relevant abilities in the prefrontal cortex include controlling impulses, awareness of future consequences, and empathy which all discourage murderous behaviour. The first thing is the distinguishing in terms of physiology between offenders and non-offenders. The prefrontal cortex can be damaged in subtle ways by childhood physical abuse and maltreatment (Teicher 2002). So the abuse leads to brain damage which leads to violence (directly or indirectly), can the perpetrator be held responsible for their actions? If an individual has no impulse control through damage to the prefrontal cortex, what is to stop them committing impulsive behaviour? Who is to blame when a car without brakes crashes? Knowing More Than the Individual Themselves Another issue is that the sophistication of the technology has led to inferences about mental states outside of conscious awareness. In other words, neuroimaging is telling us something that the individual does not consciously know themselves. The idea of the "transparent brain" (Fuchs 2006). One example of this is unconscious attitudes. The idea that there is a conscious attitude (what the individual reports on attitude questionnaires) and an unconscious attitude (what they really believe). The two may, of course, be in agreement. But more interesting when they are not, as in the case of racial attitudes. For example, white participants who did not report racist attitudes, showed greater activity in the amygdala in response to black people's faces than whites (Phelps et al 2000). This would suggest fear of these faces, and Methods and Issues of Studying the Brain in Psychology; Kevin Brewer; 2009 ISBN: 978-1-904542-48-3

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the inference of unconscious racist attitudes. More than this, inferences are made about future behaviour. For example, Arnow et al (2002) showed a link between particular sexual preferences and physiological correlates in "healthy heterosexual men". In other words, if a non-offender shows the physiological correlates associated with sexual violence in an experiment, the prediction could be made that such an individual will perpetrate sexual violence in the future. But should it be made in terms of labelling individuals before they offend? If it is possible to know more from brain scans than the individual knows themselves, it could be inferred if they are lying. "Brain fingerprinting" is based on this assumption. Developed by Lawrence Farwell (Farwell and Smith 2001), it measures P300 waves by EEG in response to knowledge of facts about a crime. The P300 wave response to crime-related words flashed on a screen are classed as "guilty knowledge" which the offender cannot hide. The key is that there will be information that is only known to the offender and the "guilty knowledge test" will find it among hundreds of questions asked. The technology is being used in the US legal system (eg: murder conviction reversal in Iowa; Fuchs 2006). One major problem stands out with "brain fingerprinting". It measures recognition, and this recognition may be from elsewhere than the "guilty knowledge" of the offender (Innovation 2004). Neuroimaging has also been used to detect deception by showing the physiological correlates of intentional deception (eg: in anterior cingulate cortex in functional magnetic resonance imaging; Langleben et al 2002). The faith in what scanning is able to tell us about the "real" or "secret" thoughts of the individual is highlighted in a system called MALINTENT (Future Attribute Screening Technology - FAST). It is a "body scanner" developed in the USA to detect terrorists in advance of an attack, for example, using measures of body temperature, heart rate, and respiration, and microfacial scanning (minute muscle movements in faces). "It is like an X-ray for bad intentions" (Barrie 2008). Wider Ethical Issues with Neuroimaging There are a number of critical issues in using neuroimaging, particularly when it goes beyond the simple description of physiology.

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1. The gap between subjective experience and electromagnetic signals. "Imaging studies are based on probabilistic covariances and not on causal connections. Their interpretation depends on the design and theory behind the study.." (Fuchs 2006 p601). It is one thing to see the brain activated during certain behaviour, and another to say what is actually going on, particularly in terms of subjective experience. This is even more so with complex social issues - eg: showing a reaction in the amygdala to a photograph flashed on a screen briefly is a very poor way of measuring racial attitudes. Attitudes, at least, involve different components - cognitive, affective, and behavioural (Secord and Backman 1964). If neuroscience comes to dominate in psychiatry, as in cognitive neuropsychiatry (CNP) (Halligan and David 2001), then diagnosis of mental disorders will depend on neuroimaging techniques. Such an approach would lead to changes in the clustering of symptoms, and the elimination of classifications like "schizophrenia", "bipolar disorder" etc. They will be replaced by "neurological explanations and to the entities that make up such explanations instead" (Fuser-Poli and Broome 2006 p610). So at the moment, depression would be diagnosed based on the presence of behavioural symptoms like low mood and suicidal thoughts, diagnosis in CNP would revolve around brain abnormalities. Depression would equal the specified abnormalities in the particular areas of the brain. Behavioural symptoms would simply be a product of these brain abnormalities. The mind, as in subjective experience, is removed from the process. This has been called "eliminative mindless psychiatry" (Jablensky and Kendell 2002). 2. From potential to actual. It is one thing to say that the individual has the physiology for potential violence and another for them to show it. There are many factors between the potential and actual. Brewer (2003) distinguished three groups of factors (individual, group and social) that lead to a general level of aggression, but then disinhibitions and environmental triggers that explain the specific aggression shown. This move from general to specific is similar to the move from potential to actual. There are a lot of concerns if individuals are Methods and Issues of Studying the Brain in Psychology; Kevin Brewer; 2009 ISBN: 978-1-904542-48-3

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punished for having the potential to be dangerous. Though we live in a society that is trying to pursue such ideas. The ability to predict future behaviour is the holy grail of psychology and psychiatry. Sometimes it is done well, many other times done badly. "The wide-spread misunderstanding of brain scans as direct measures of psychological states or even traits, however, carries the risk that courts, parole boards, immigration services, insurance companies and others will use these technologies prematurely" (Fuchs 2006 p601). 3. Acting on the knowledge. In the area of mental illness, studies have looked for pre-onset factors to predict the mental disorders. For example, functional magnetic resonance scans of adolescents with a high family risk of schizophrenia show brain differences (eg: Pantelis et al 2003). To act upon this knowledge could mean giving these adolescents anti-psychotic drugs before any behavioural symptoms have appeared. Such drugs have effects on the brain as well as producing side-effects. How long to remain on the medication? Not to mention the potential for discrimination from others, and the effects of the knowledge on the individual's self-esteem (Fuchs 2006). 4. Technology as threatening. "Our sense of privacy may be threatened by technologies that can reveal the neural correlates of our innermost thoughts and unconscious attitudes" (Fuchs 2006 pp601-602). At the moment, such technology is relatively limited in this, but what if it becomes more reliable and accurate in the future. This is a threat to "cognitive liberty" - an individual's right over their own brain and its contents (Sententia 2004).

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8. NEW AND MISCELLANEOUS TECHNIQUES 1. Computer Modelling Neural networks can be used to model human cognition, and then parts "turned off" to show the effect of brain damage (Mayall 1998). 2. Transgenic and Knockout Animals Modern genetic engineering allows for animals to be "produced" which lack a gene of interest ("knockout") or have a gene from a human, say (transgenic). For example, knockout mice have been engineered that cannot produce the neurotransmitter, orexin (Siegel et al 2001). 3. Reverse Engineering This involves speculating about the function of a behaviour in the evolutionary past from its current existence (Tooby and Cosmides 1992). 4. Thought Experiments These are philosophical puzzles that help researchers to think about the issues in consciousness. For example, in the "zombie thought experiment", a molecule by molecule replica of a conscious human being is made. Is this replica ("zombie") conscious? How this question is answered links to the view taken about consciousness (Braisby 2002).

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9. ISSUES AND DEBATES 9.1. MIND-BRAIN RELATIONSHIP The focus is upon how to study the brain (the physical organ), but what is its relationship with the mind or consciousness (the subjective experience). Rene Dēscartes, in the seventeenth century, distinguished between the mind and the body in an idea now called dualism. The body was described as a "machine" while the mind (or soul) is non-material and located in the pineal gland. This established the principle of the mind and the brain/body as different. Dualism would mean that the mind could exist in the absence of the body (Toates 2004). The alternative to dualism is monism, which sees the mind and brain as one. There are also theories which attempt to reject both monism and dualism. Searle (1999) distinguished two types of dualism in philosophical terms:



Substance dualism - the universe is divided into material objects and immaterial minds; Property dualism - there are physical properties (eg: how much an object weighs) and mental properties (eg: subjective experience).

In each case, the two elements are mutually exclusive. The different relationships between the mind and the brain can be summarised thus (Gross 1992): 1. Dualism: The mind and body/brain are causally related. i) Interactionism There is a two-way relationship between the mind and the body/brain. The mind can influence the body/brain as in psychosomatic illness or the placebo effect, while the body/brain can influence the mind (eg: drugs that change perception or brain damage changing personality). Strength - Fits well with common sense. Weakness - How do they actually influence each other? ii) Epiphenomenalism The causal relationship is only in one direction (ie: the physical influences the mental). In fact, mental Methods and Issues of Studying the Brain in Psychology; Kevin Brewer; 2009 ISBN: 978-1-904542-48-3

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experiences are by-products of physical processes. The mind or consciousness is "just a kind of vaporous residue cast off by the brain, but is unable to do anything on its own" (Searle 1999 p58). Strength - Concentrates upon the brain which can be seen and studied. Weakness - Does not explain how mental processes are a by-product of physical processes. 2. Dualism: The mind and body/brain are correlated but causally independent. Psychophysical Parallelism Originally proposed by Leibniz in the eighteenth century, mental and physical processes occur simultaneously but independent of each other (ie: not causing one another). For example, the mental experience of perceiving an object occurs at the same time as the physical processes involved (neurons firing in different parts of the brain). Strength - Allows for both the mind and the body to be studied separately. Weakness - Often there is no simple correlation between a physical and a mental process. For example, the mental experience of depression can occur in response to different physical states or processes. 3. Dualism: The mind and body unrelated. 4. Monism: The mind and the brain are the same. i) Idealism/Mentalism Based on the original idea of George Berkeley, in the nineteenth century, only mental processes are real. This idea saw the mind as only existing and the brain exists as ideas in that mind. "Transcendental idealism", from Immanuel Kant, "maintains that the fundamental categories in terms of which we characterise the world are not objective features of things in themselves but are structures imposed by the mind; without such organising structures experience would not be possible" (Haugeland 1987 p337). Strength - "Transcendental idealism" emphasises how Methods and Issues of Studying the Brain in Psychology; Kevin Brewer; 2009 ISBN: 978-1-904542-48-3

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structures of the mind (meanings) make sense of the physical world. Weakness - Idealism seems to be anti-common sense. ii) Materialism (or physicalism) Only physical processes are real. In other words, the mind is the product of the brain: cells firing in a certain way produces the experience of consciousness (eg Dennett). Strength - It is a view held by many scientific psychologists, and it holds out hope of finding the physical basis to all experiences. Weakness - Reductionist: subjective experience is reduced to physiology. iii) Identity Theory This is a recent development of Materialism which emphasises that consciousness is a brain process. They are the same thing, but have different meanings, like the words, "sister" and "female sibling". The two words describe the same person, but the meaning of each is different. So the language is important. Strength - As Materialism. Weakness - As Materialism. iv) Panprotopsychic Identism (or Panpsychism) This is the view that consciousness exists in all matter, and that "all physical things have a mental side, aspect, or properties, even if in a primitive and undeveloped form" (Armstrong 1987 p491). Strength - Offers a "spiritual" view to counter Materialism. Weakness - Difficult to study scientifically. 5. Alternatives to Monism and Dualism. i) Double-aspect theory (Valentine 1982) Both the mind and the brain are real, but they are Methods and Issues of Studying the Brain in Psychology; Kevin Brewer; 2009 ISBN: 978-1-904542-48-3

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aspects of a "fundamental underlying reality". Strength - Tries to break out of the monism-dualism dichotomy. Weakness - Not clear what the "fundamental underlying reality" is. ii) Naturalistic Functionalism Developed by William James, consciousness ("Conscious Mental Life") has evolved via natural selection among species with a certain type of brain. Consciousness (the mind) is an "emergent property" of the physical brain, but, at the same time, distinct from it. Strength - Explains the development of the mind through the theory of evolution. Weakness - How is the mind both a product of and distinct from the brain? iii) Computational Theory of the Mind This is a recent development of the last view, and uses the computer analogy of software/hardware. The brain is the hardwire and the mind is the software. Strength - Gives a basis for developing computer models of the mind and brain. Weakness - Reductionist: the computer analogy is limiting. 9.2. CONSCIOUS AND NOT CONSCIOUS There is the conscious part of the mind, and the other part. This other part can be called "notconscious", though many other terms have been used like unconscious, sub-conscious, or pre-conscious. Work on the physiology of the brain in recent years has played down the importance of the conscious part as seen in this quote: "the normal unconscious brain monitors the mirror for cues that prompt it to decide whether to awaken and engage.. The decision to engage at all is, in effect, an unconscious decision to be conscious" (Michael Shadlen quoted in Douglas 2007). Here are some categories of conscious and notconscious. It is an attempt to clarify the different Methods and Issues of Studying the Brain in Psychology; Kevin Brewer; 2009 ISBN: 978-1-904542-48-3

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ideas rather than being exhaustive. 1. Conscious The part of the mind that the individual is fully aware of. Early psychology focused on conscious thought through introspection, while con awareness is key to humanistic and experiential psychology (Stevens 1996). 2. Unconscious Sigmund Freud (1923/1991) saw the majority of the mind as inaccessible to consciousness, but still determining behaviour. It is the originator of the "real" motive for behaviour rather than the conscious (illusory) explanation given. Technically, it is known as the "dynamic unconscious". 3. Pre-conscious This is the part of the mind that the individual can become aware of when required. For example, the recall of stored memories. Memories are not conscious until recalled. 4. Outside consciousness This category is used to cover automatic physiological processes that individuals have no conscious control over (eg: breathing, digestion). These processes continue irrelevant of the individual's conscious state, like during sleep. 5. Automatic behaviours Learned behaviours or skills can be performed without conscious attention, and in well practised cases, do better without conscious thought. It is possible to focus consciously upon them if necessary. 6. Non-conscious This category is the most challenging to the understanding of the conscious self. It is the situation where physiological measures show brain activity, but the individual reports no conscious awareness (eg: subliminal perception). Methods and Issues of Studying the Brain in Psychology; Kevin Brewer; 2009 ISBN: 978-1-904542-48-3

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For example, in the case of blindsight, individuals with damage to the visual cortex report blindness, but when asked to guess a position of an object in their blindfield do so correctly. It is almost an "unconscious seeing and a conscious blindness". 7. Unawareness This category is included to cover lack of insight and not noticing things. For example, individuals may not be aware of the effect of their behaviour on others, but they can be made aware by others telling them or by selfreflection. This can be called "consciousness-raising". Non-Conscious Non-conscious brain activity is studied by flashing a stimulus on a screen for a very short time. Individuals fail to report seeing anything if the duration is less than 50ms, but the brain registers the stimulus even when not consciously seen (as measured by electrical activity)(eg: Del Cul et al 2007). The question is whether the conscious/non-conscious are parts of the same system or separate systems. In the case of the latter, for example, Daw et al (2005) have described four systems (two conscious and two nonconscious)(Douglas 2007):


Pavlovian controller (non-conscious) - controls routine, reflexive, and instinctive behaviour;




Habitual controller (non-conscious) - controls habitual, learned behaviour like driving;




Episodic controller (conscious) - in control in unfamiliar situations, and when learning is new;




Goal-directed controller (conscious) - rational decision-making.

In Halligan and Oakley's (2000) two-level model, most cognitive processes occurs at level 2 (nonconscious), which includes the central executive system (CES). Level 1 is conscious awareness and voluntary control. The CES creates the belief in the self, and maintains a consistent self and a biography along with the illusion of control 10.

10

Another debate relates as to whether we have free will and conscious control over our behaviour .

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Non-Conscious Decision-Making The declining importance of conscious thought includes the case of making decisions. "An example of unconscious thought is the following: One compares two holiday destinations (say the Costa Brava and Tuscany) and does not know what to decide. One puts the problem aside and after 48 hours of not thinking about it consciously, suddenly the thought 'It's going to be Tuscany!' pops into consciousness. This thought itself is conscious, but the transition from indecision to a preference 2 days later is the result of unconscious thought, or of deliberation without attention" (Dijksterhuis et al 2006 p1005). Dijksterhuis et al (2006) have called this the "deliberation-without-attention" effect. They argue that conscious thought is better for simple decisions, but unconscious decisions are better with complex choices. This was formalised in the "unconscious thought theory" (UTT)(Dijksterhuis and Nordgren 2006). Basically unconscious thought is able to find patterns which conscious thought can do because the latter is "rulebased and very precise". Dijksterhuis et al (2006) offered participants a choice of four cars based on a series of attributes. In the simple decision, there were four attributes, and twelve with the complex decision. The attributes were positive or negative, and altered for each car - one car 75% positive/25% negative, 50%/50% for two cars, and one car 25% positive/75% negative. One group were asked to think carefully for four minutes about their decision (conscious decision-making) while the other group had to solve anagrams as a distraction task for four minutes (unconscious decisionmaking). The latter group made the better choice for the complex decision, and the simple decision was better in the conscious decision-making group (table 26).

SIMPLE DECISION

COMPLEX DECISION

CONSCIOUS DECISION-MAKING

55

20

UNCONSCIOUS DECISIONMAKING

40

60

(After Dijksterhuis et al 2006)

Table 26 - Percentage of participants who chose most desirable car. Dijksterhuis et al (2006) performed three other Methods and Issues of Studying the Brain in Psychology; Kevin Brewer; 2009 ISBN: 978-1-904542-48-3

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experiments about choices of consumer goods and found the same principle. They concluded: Although we investigated choices among consumer products in our studies, there is no a priori reason to assume that the deliberationwithout-attention effect does not generalize to other types of choices—political, managerial, or otherwise. In such cases, it should benefit the individual to think consciously about simple matters and to delegate thinking about more complex matters to the unconscious (p1007).

Lassiter et al (2009) replicated the complex decisions in the experiment, but added conditions which asked participants (university students) to memorise the cars' attributes as well. In this case, the conscious decision-making group did better (table 27).

THINK CAREFULLY

SOLVE ANAGRAMS

DIJKSTERHUIS ET AL REPLICATION

0.80

1.78

MEMORISE ATTRIBUTES

1.95

0.92

(Higher score = better decision) (After Lassiter et al 2009)

Table 27 - Mean preferences for car with most positive attributes. This work challenges that of Dijksterhius et al, but it does not necessarily support conscious decisionmaking. For the researchers the decision is made on "an immediate gut instinct" (Schultz 2009). This is supported by Cleeremans (quoted in Schultz 2009) who used a similar experiment to test decisionmaking on apartments based on a series of attributes. Decisions made immediately were as good as those made by the unconscious decision-making group. Central Executive Another question related to consciousness is whether the brain has a central place or executive that controls its activities. The common sense belief and historical view is that there is a central executive in the brain. This is sometimes called the "Cartesian theatre", where consciousness lives and is controlled. Descartes believed Methods and Issues of Studying the Brain in Psychology; Kevin Brewer; 2009 ISBN: 978-1-904542-48-3

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that the brain had a centre, which he said was the pineal gland. Also early theories of the brain believed that a "little man" (homunculus) sat inside and controlled everything that happened (Dennett 1991). In terms of cognitive processes, Norman and Shallice (1986) developed the idea of a central executive that controlled attention, memory, and willed actions 11. Modern theories of the brain tend to reject the idea of such a place in the brain. "Rather than a central executive, there seems to be a network of brain regions that organise the resting state and maintain overall orientation towards context" (Shadlen and Kiani 2007). Neuroimaging scans during performance of attentiondemanding cognitive tasks produced two patterns of brain activity - increased activity in frontal and parietal cortical regions and reduced activity in other areas including the medial prefrontal cortex (Fox et al 2005). This supports the notion of opposing or competing processes in the brain, which is popular in a number of recent theories (Blackmore 2002). Dosenbach et al (2007) confirmed the idea of to distinct "task-control networks" in the brain - the fronto-parietal network and the cingulo-opercular network. The feeling that we have that there is a control place in the brain where we "live" is an illusion created by the brain (Blackmore 2002).

11

Some implicit processing produces prefrontal cortex activity similar to explicit processing/conscious awareness (Badgaiyan 2000). Methods and Issues of Studying the Brain in Psychology; Kevin Brewer; 2009 ISBN: 978-1-904542-48-3

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10. REFERENCES Allen, E.A et al (2007) Transcranial magnetic stimulation elicits coupled neural and hemodynamic consequences Science 317, 1918-1921 Amassian, V.E et al (1989) Suppression of visual perception by magnetic coil stimulation of human occipital cortex Electroencephalography and Clinical Neurophysiology 74, 458-462 Anonymous (1851) A most remarkable case American Phrenological Journal and Repository of Science, Literature, and General Intelligence 13, 89, col.3 Aribandi, M (2008) Corpus callosum, agenesis (http://www.eMedicine.com/radio/topic193.htm/; accessed 16/11/08) Armstrong, D.M (1987) Mind-body problem: Philosophical theories. In Gregory, R.L (ed) The Oxford Companion to the Mind Oxford: Oxford University Press Arnow, B et al (2002) Brain activation and sexual arousal in healthy heterosexual males Brain 125, 1014-1023 Aviezer, H et al (2007) Implicit integration in a case of integrative visual agnosia Neuropsychologia 45, 9, 2066-2077 Badgaiyan, R.D (2000) Executive control, willed actions, and nonconscious processing Human Brain Mapping 9, 38-41 Baldwin, A & Berkoff, M (2007) Ignoring stress in lab animals could mar research New Scientist 2/6, p24 Barker, A.T et al (1985) Non-invasive magnetic stimulation of human motor cortex Lancet 1, 1106-1107 Barnard, N.D & Kaufman, S.R (1997) Animal research is wasteful and misleading Scientific American February, 64-66 Barrie, A (2008) Homeland security detects terrorist threats by reading your mind www.foxnews.com 23/9 (accessed 3/11/08) Battelli, L et al (2003) Bilateral deficits of transient visual attention in right parietal patients Brain 126, 2164-2174 Battelli, L et al (2008) The "when" parietal pathway explored by lesion studies Current Opinion in Neurobiology 18, 120-126 Baxter, I et al (1992) Caudate glucose metabolic rate change with both drug and behaviour therapy for obsessive-compulsives Archives of General Psychiatry 49, 681-689 Beckers, G & Zeki, S (1995) The consequences of inactivating areas V1 and V5 on visual motion perception Brain 118, 49-60 Berger, A (2002) How does it work? Magnetic resonance imaging British Medical Journal 5/1, p35 Berger, H (1929) Über das Elektrenkephalogramm des Menchen Archives fur Psychiatrie 87, 527-570 (In German) Bigelow, H.J (1850a) Dr.Harlow's case of recovery from the passage of an iron bar through the head American Journal of Medical Sciences 20, 13-22 Bigelow, H.J (1850b) Dr.Harlow's Case of Recovery from the Passage of an Iron Bar Through the Head Philadelphia: Collins Blackmore, S (2002) The grand illusion New Scientist

22/6, 22-29

Blasdel, G.G (1992) Orientation selectivity, preference, and continuity in monkey striate cortex Journal of Neuroscience 12, 3139-3161

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11. APPENDIX

(Source: In public domain)

Figure A - Paul Broca.

(Source: McGill University Archive; out of copyright; in public domain)

Figure B - Wilder Penfield.

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