Revision

Biological Approach – Study Guide Revision THEORY OF LOCALIZATION    

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Theory of localization, weak localization, strict localization, widely distributed functions Cortical homonculus (Penfield, Boldrey, 1937) - attempt to establish areas (through strict localization). Used the method of neural stimulation. Example of early studies/ideas: Broca’s aphasia, Wernicke’s aphasia Previous approach: Strict localization inspired by post-mortem examination of brains of patients with speech disorders. It appeared that the production of speech is located in Broca’s area and comprehension in Wernicke’s area. Current approach to localization: Weak localization. Several areas of brain responsible for the function and can take over, however, only one of the areas is dominant. Supporting research, which demonstrates that language (its production and comprehension) are weakly localized: Sperry (1968), Gazzaniga (1967) (split-brain patients: 1) language is in the left hemisphere + the right hand, 2) weak localization of speech comprehension + pencil, 3) language production can be in the right hemisphere in some people Lateralization – the division of function between the right and left hemisphere Paul Broca (1861) Broca’s area – posterior inferior frontal gyrus. (“Tan”) Carl Wernicke (1874) Wernicke’s area – brain responsible for comprehension of written and spoken language. Temporal lobe of the dominant hemisphere. Karley Lashley (1929) – some psychological functions are disturbed rather than localized. The principle of mass action and equipotentiality, study was focused on memory. Localization of function is relative – the idea includes 5 aspects (study guide) Some functions are strictly localized - Paul Broca (1861), Carl Wernicke (1874) Some functions are widely distributed - Karley Lashley (1929) Some functions are rather weakly localized than strictly (several areas responsible, one dominant) Sperry (1968), Gazzaniga (1967) Some components of a function may be localized, while others can be distributed (speech comprehension is more localized) Localization is not static (neuroplasticity) Hippocampus – part of the limbic system implicated with emotional regulation and long-term memory

NEUROPLASTICITY  

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Neuroplasticity – the ability of brain to change through the making and breaking of synaptic connections in response to environmental demands Synaptic plasticity - neuroplasticity on the level of a single neuron, construction of a new synaptic connection and reduction of the one not used o Occurs on the scale from: synaptic plasticity to local remapping Merzenich et al (1984) – specific neurological unit – sensory cortex Draganski et al (2004) – neuroplasticity is the neural basis of learning (used brain imaging technique: MRI) Maguire et al (2000) – redistribution of grey matter in anterior/posterior cortex (used brain imaging technique: MRI) o Important aspect: Posterior hippocampus is responsible for using previously learned spatial information, whereas anterior hippocampus is responsible for learning new spatial information Definitions: agonist, antagonist, neurotransmitter, of which parts neuron is built (the body, dendrites, the axon)

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Neurotransmission is both chemical and electrical: Crockett et al (2010) – serotonin and prosocial behavior (citalopram, a SSRI drug, and placebo used) Freed et al (2001) – transplantation of dopamine-producing cells reduces symptoms of Parkinson’s disease (used brain imaging technique: PET) Fisher, Aaron and Brown (2005) – dopaminergic activity as the basis of the feeling of love (used brain imaging technique: fMRI) Discuss limitations of neurotransmitter research (the effect of used drug on neurotransmitter might seem like direct but it isn’t, effect might be postponed, drug might be not the only factor influencing neurotransmitter, side effects) Definitions vol 2: BOLD (bloox-oxygen-level-dependent) signal, used in fMRI Changes in brain research: o From post-mortem autopsies to:  Computerized Axial Tomography (CAT)  Positron emission tomography (PET)  Magnetic Resonance imaging (MRI)  Functional Magnetic Resonance Imaging (fMRI)  Electroencephalography (EEG) Know the comparison of brain techniques

HORMONES AND PHEROMONES        

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Definitions: Endocrine system, Oxytocin, Pheromone, Putative human pheromone Comparison of hormones and neurotransmitters: different means of communication and different processes regulated Chemical hypothesized to be a human pheromone signaling sexual attractiveness must: 1) signal gender and 2) affect perceived attractiveness of the faces of the opposite sex Roles of oxytocin and production: released in pituitary gland, roles: sexual reproduction, social bonding, childbirth Feurgson et al (2000) – social amnesia in mice lacking the oxytocin gene, gene knockout, discussion about recognizing familiar members of the same species Scheele et al (2012) – fidelity in humans, oxytocin causes men in a relationship to keep greater distance form attractive women who are not their partner (and this promotes fidelity) Pheromones are processed in olfactory bulb, consisting of an organ known as VNO (vomeronasal organ) connected to the brain region known as accessory olfactory bulb Difference between pheromones and chemical messengers: pheromones communicate information form one species to another Putative human pheromones studies: Lundstrom and Olsson (2005) – effect of androstadienone on the mood of women in the presence of men (it might serve as a signal of sexual attractiveness) Hare et al (2017) – effect: neither androstadienone nor estratetraenol perform functions of pheromones (3rd point) Cutler, Friedman, McCoy (1998) – investigation of the effect of a synthesized human pheromone on the sociosexual behavior of men (the results were that the pheromone increased sexual attractiveness of men to women) Criticism of human pheromone research – inconclusive, contradictory findings (ex: Lundstorm and Ollson, hare et al), involves companies financially interested in the results (Cutler, Friedman, McCoy, 1998), ecological and internal validity, demand characteristics

GENETICS AND BEHAVIOR  

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Gene, Gene expression, Gene transcription and translation, Genotype, Phenotype Nature-nurture debate: Is human behavior determined by biological factors or environmental influences? o Example of twin study: Bouchard and McGue (1981), heritability of intelligence, used MZ and DZ twins. Twin studies compare similarity between monozygotic and dizygotic twins for particular trait or behavior. o Example of adoption study: Scarr and Weinberg (1983), contradictory results of the study demonstrate the idea of additive influence. Adoption studies investigate the relationship between socioeconomic status of families and IQ of biological and adoptive parents o Example of study with molecular genetics: Caspi et al (2003), people with one or two short alleles of the 5-HIT gene are more vulnerable to stress. o Example of epigenetic study: Weaver et al (2004), rat adoption study. Epigenetic study use genetic mapping technology. o Family studies – collecting data about families throughout several generations. Genetic relatedness is compared to observed similarities. Theory behind the topic/terms: The Falconer model: phenotypical variation of a trait is explained by the contribution of genetic inheritance, shared environment and individual environment. This model is used with twin research data to quantify the relative contribution of heredity to a trait or behavior. Niche-picking: How genetic factors can influence the environment. It presumes that genetic predisposition causes individuals to select certain niches

 EVOLUTIONARY EXPLANATION  

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Definitions: adaptation, disgust, evolution, massive modularity, natural selection, post-hoc reasoning How these studies look like: a phenomenon universal for humans is selected (ex. disgust), evolutionary explanation for this phenomenon serves as a model upon which predictions are made and tested to see the validity of the model Theory of evolution (Charles Darwin, 1859): 4 principles o Organisms are driven by the need to survive and reproduce o Differential fitness: organisms having different traits are adapted to their environment to varying degrees

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o Better-adapted organisms have higher chances of survival o Less-adapted organisms produce less offspring so their genes “disappear” Curtis, Aunger, Rabie (2004) – evolutionary explanation for disgust. It supported the evolutionary explanation. Was based on 4 assumptions: o Disgust should be stronger in response to stimuli associated with disease o Disgust responses should be similar cross-culturally o Disgust should be more pronounced in females (they have to protect their and babies’ immune system) o We are older = reproductive potential declines = we are less disgusted by something Know about criticism of evolutionary explanations: massive modularity vs neuroplasticity, speculations about environment, testability, cultural variation