Cerebral Cortex 2

Forebrain2: Subcortical Telencephalon Bill Truitt MS 513 Off 278.9050 Lab 278.9110 [email protected]

Overview Components, location and

function of the basal forebrain

Components, location and

function of the basal ganglia

Components, location and

function of the limbic system

Basal Forebrain Structures Group of ill-defined structures deep to ??? APS: •Identifiable by perforations of branches of ??? •Bordered by ???

Basal forebrain structures:

AC

•???: Olfactory tubercle •??? •In / near ventral striatum •Rostral to AC •Anterolateralto hypothalamus •e.g., Basal nucleus of Meynert, nucleus accumbens, septal nuclei

Basal (inferior)

Haines 156

3

Basal Forebrain Structures Group of ill-defined structures deep to anterior perforating substance (APS) APS: •Identifiable by perforations of branches of ACA &by MCA •Bordered LOS, MOS of OT

Basal forebrain structures:

AC

•APS gray: Olfactory tubercle •Subcortical nuclei deep to •APS In / near ventral striatum •Rostral to AC •Anterolateralto hypothalamus •e.g., Basal nucleus of Meynert, nucleus accumbens, septal nuclei

Basal (inferior)

Haines 156

4

Basal Forebrain at ??? Le vel Coronal section at optic chiasm  ??? (Ventral Striatum)  Most ventral portion of the striatum, where caudate and putamen are continuous (no longer separated by anterior branch of int. capsule  ???

coronal section

of sect io n

AC

Rostral to AC:

Haines 1516

Haines 156

5

Basal Forebrain at Le vel optic chiasm of Coronal section at optic chiasm

sect io n

 Nucleus Acumbens (Ventral

Striatum)

AC

Rostral to AC:

 Most ventral

portion of the striatum, where caudate and putamen are continuous (no longer separated by anterior branch of int. capsule



coronal section

Haines 1516

Haines 156

6

Basal Forebrain at ????

Coronal section at level of ???  Located within APS  ???  AKA substantia innominata  ???

 Medial Septal

Le vel of sect io n AC

Med septal N.

Nucleus  ???

N. diagonal band.

Basal nucleus of Meyner t Haines 1516

coronal section

7

Basal Forebrain at AnteriorCommissure Coronal section at level of anterior commissure and column of fornix  Located within APS

Le vel of sect io n AC

 Basal Nucleus

of Meynert  AKA

Med septal N.

substantia innominata

 Nucleus of

Diagnal Band

 Medial Septal

Nucleus

N. diagonal band.

 Anterior to

column of

Basal nucleus of Meyner t Haines 1516

coronal section

8

Basal Forebrain Structure provide ??? inputs to cortex neocortex

BF structures •S •<: 1% ize cortical mass

•Function: •???(emoti ons) •??? (rational thought) •??? regulate its excitabilit y

allocorte x Martin 3-17

Alzheimer’s Disease: degeneration of BF cholinergic inputs to

10

Basal Forebrain Structure provide Cholinergic inputs to cortex neocortex

BF structures •S •<: 1% ize cortical mass

•Function: •Limbic (emotions •)HCF (rational thought) •Diffuse cortical projection allocorte s regulate x its Martin 3-17 excitabilit Alzheimer’s Disease: degeneration of BF cholinergic inputs to y

11

Basal Ganglia

Not a ganglia (Nuclei – central)

Dorsal component  ?? + ???

Ventral component

Insula

Putamen

Globus Pallidus externa

Globus Pallidus interna

 ???  parts of

adjacent ???  ???

Interconnected structures

Claustrum

Basal Ganglia

Not a ganglia (Nuclei – central)

Dorsal component  Caudet +

lentiform nuclei

Ventral component

Insula

Putamen

Globus Pallidus externa

Globus Pallidus interna

 Nucleus

Accumbens  parts of adjacent olfactory tuberal  Substantiainnomi nata

Interconnected

Claustrum

Basal Ganglia:Basal Motor Nuclei

unctional components (basal-motor nuclei) include caudate, putamen, globuspallidus, subthalamus, substantianigra. (Telencephalic BG: caudate, putamen,GP) (Diencephalic: subthalamus) (Midbrain: substantianigra) erminology audate + Putamen = Striatum (or neostriatum) orpus striatum = caudate/putamen + globuspallidus  Paleostriatum = globuspallidus

utamen + globuspallidus = lentiform nuclei lobuspallidus contains an external (Gpe) and an internal (Gpi) part

Circuit loop of motor cortical areas with basal-motor nuclei and thalamus

Nolte 13-6

 Multiple cortical areas send cortico-striate fibers  

 

to ??? Striatum interconnected with ??? Two major ??? to motor thalamus (??,??)  ??? is major output of lentiform nuclei to the ???  ?? projections to thalamus Subthalamus reciprocally interconnected with ??? ??? inhibit tonic level of activity in motor thalamus,

Circuit loop of motor cortical areas with basal-motor nuclei and thalamus

Nolte 13-6

 Multiple cortical areas send cortico-striate fibers to

striatum  Striatum interconnected with substantianigra  Two major inputs to motor thalamus (VA, VL)

 Gpi is major output of lentiform nuclei to the motor

thalamus  Nigral projections to thalamus

 Subthalamus reciprocally interconnected with

Forebrain: Basal Motor Nuclei Motor cortical areas

Motor cortical areas

+ CST loop

+

+

E

loop

E

I

-

DIRECT PATHWAY

I

+

contra

•Motor loop: ???

-

-

Nolte 13-6

INDIRECT PATHWAY

•M. cort. areasstriatumGpithalamus (VA/VL)M. cort areas •Substantia nigra interconnected with striatum (e.g., nigrostriatal proj.) •Subthalamus reciprocally interconnected with GP

•Gpi: major lentiform output (???) to motor thalamus

•Basal-motor nuclei (-) tonic (spont.) activity of motor thalamus, and thus modulate CST outputs: BMN modulate ??? movement 18

Forebrain: Basal Motor Nuclei Motor cortical areas

Motor cortical areas

+ CST loop

+

+

E

loop

E

I

-

DIRECT PATHWAY

I

+

contra

•Motor loop: ipsilateral

-

-

Nolte 13-6

INDIRECT PATHWAY

•M. cort. areasstriatumGpithalamus (VA/VL)M. cort areas •Substantia nigra interconnected with striatum (e.g., nigrostriatal proj.) •Subthalamus reciprocally interconnected with GP

•Gpi: major lentiform output (-) to motor thalamus

•Basal-motor nuclei (-) tonic (spont.) activity of motor thalamus, and thus modulate CST outputs: BMN modulate contra movement 19

Relative Location of Deep Structures

Basal ganglia

Thalamus

Internal capsule

Hypothalamus

Coronal section at level of Posterior

20

Relative Location of Deep Structures

Basal ganglia

Thalamus

Internal capsule

Hypothalamus

Coronal section at level of Posterior

21

Lesions and Deficits of Basal Motor Nuclei

Lesions and Deficits of Basal Motor Nuclei

Limbic Lobe  Limbic lobe  Parolfactory area  Subcollosal gyrus  Cingulate gyrus  Parahippoca mpal gyrus  Uncus  Internal

Structures  Hipp, hyp,

Limbic Lobe  Limbic lobe  Parolfactory area  Subcollosal gyrus  Cingulate gyrus  Parahippoca mpal gyrus  Uncus  Internal

Structures  Hipp, hyp,

Classifying limbic structures Accepted limbic structure

Mostly Accepted

Cingulate Gyrus*

Thalamic nuclei interconnected w/limbic structures

Parahippocampalgrus*

Neocortexinterconnected w/limbic structures i.e. Frontal cortex, orbital cortex

Hippocampal formation* Amygdala* Septal Area* Nucleus Accumbens Substantiainnominata Hypothalamus Mamilliary bodies Anterior thalamic nuclei Midbrainreticularformation (parts)

Papez Circuit

Limbic lobe Papez circuit

thalamus

hypothalam us Dysfunction of limbic structures underlies virtually all psychiatric disorders

27 27

Papez Circuit

Limbic lobe Papez circuit

thalamus

hypothalam us Dysfunction of limbic structures underlies virtually all psychiatric disorders

28 28

Amygdaloid Complex lmond shaped structure in the ???, deep to the ??? ostral to anterior end of temporal horn of lateral ventrical omposed of multiple nuclei that are grouped into:  ??? – interconnected with

cortical areas  ??? – closely related to olfaction

Amygdaloid Complex lmond shaped structure in the Rostromedial temporal lobe, deep to the uncus ostral to anterior end of temporal horn of lateral ventrical omposed of multiple nuclei that are grouped into:  Basolateral amygdala –

interconnected with cortical areas

 Corticomedial (AKA

extended amygdala) –

Amygdaloid asolateral Nuclei: Complex: refrontal cortex cingulate/prahippocampalgyri, temporal lobe andinsular cortex Afferents orsal thalamus ubiculum

orticomedial Nuclei lfactory fibers from hypothalamus halamus (dorsomedial and median nuclei) rainstem nuclei associated with visceral functions (ie. NTS and periaquiductal grey)

Amygdaloid Complex: Efferents -???

Stria terminalis

Sept al nucl AC ei

Hypothalamus

Amygdala 37

Amygdaloid Complex: Efferents -Striaterminalis

Stria terminalis

Sept al nucl AC ei

Hypothalamus

Amygdala 38

Lesions/deficits of Amygdaloid Complex

Hippocampal formation ocated in the ??? uperior/lateral aspects are the floor of the inferior horn of the lateral ventricle nferior/medial border is entorhinal cortex ostralborder is Amygdala audally becomes

Hippocampal ocated in the medial formation temporal lobe uperior/lateral aspects are the floor of the inferior horn of the lateral ventricle nferior/medial border is entorhinal cortex ostralborder is Amygdala audally becomes

Hippocampal formation ocated in the medial temporal lobe

uperior/lateral aspects are the floor of the inferior horn of the lateral ventricle nferior/medial border is entorhinal cortex ostralborder is Amygdala audally becomes

Hippocampal formation cont.

Hippocampu

Allocortex of Brodmann  ???  Narrow band along

medial aspect of hipp  Receives most cortical inputs

 ???  Between DG and

subiculum  AKA hippocampus proper, Ammon’s horn

 ????  Laterally continuous with

cortex of parahippocampal gyrus  Loci of most efferent cell

Dentate Gyrus Subiculum

Hippocampal formation cont.

Hippocampu

Allocortex of Brodmann  Dentate gyrus  Narrow band along

medial aspect of hipp  Receives most cortical inputs

 Hippocampus  Between DG and

subiculum  AKA hippocampus proper, Ammon’s horn

 Subiculum  Laterally continuous with

cortex of parahippocampal gyrus  Loci of most efferent cell

Dentate Gyrus Subiculum

Hippocampal Afferents ???  Information from all

association areas of neocortex

 Entorhinal cortex

considered gateway to the hippocampus

???  Hypothalamus, Septum

(ACh), and contralateral hippocampus

???  Midbrain reticular

formation

 Raphe nuclei –

Hippocampal Afferents Entorhinal cortex (Perforant Pathway)  Information from all

association areas of neocortex

 Entorhinal cortex

considered gateway to the hippocampus

Fornix  Hypothalamus, Septum

(ACh), and contralateral hippocampus

Diffuse midbrain afferents  Midbrain reticular

formation

Hippocampal Formation Efferents Efferent cells (???)  ???, pyramidal cell of

hippocampus (lesser)  ???  ??? ??? ???

Fornix projections  ??? (to contralateral

hippocampus)  Anterior commissure divides:  ??? (terminations)  Mammillary nucleus (majority)  Thalamus (anterior dorsal)  Hypothalamus (ventromedial)  ??? (trerminations) Septal nuclei, medial frontal cortex, hypothalamus, nucleus accumbens  From the hippocampus 

Hippocampal Formation Efferents Efferent cells (Glutamatergic)  Subiculum, pyramidal cell of

hippocampus (lesser)  Axons  alveus Fimbria Fonix

Fornix projections  Hippocampal decussation (to

contralateral hippocampus)  Anterior commissure divides:  Postcommissural fornix

(terminations)

Mammillary nucleus (majority)  Thalamus (anterior dorsal)  Hypothalamus (ventromedial) 

 Precommissural fornix

Limbic control of Memory Associatio n Cortex

Acetyl Choline

Lesions/deficits of Hippocampal Form.

Lesions/deficits of Hippocampal Form.

Limbic System Structures/Funct.  ???: Involved in signaling the cortex of motivationally significant stimuli

such as those related to reward and fear in addition to social functions such as mating.  ???: Required for the formation of long-term memories  ???: Plays a role in the formation of spatial memory and is part of the   



hippocampus ???: Autonomic functions regulating heart rate, blood pressure and cognitive and attentional processing ???: Major white matter tract, carries signals from the hippocampus to the mammillary bodies and septal nuclei – involved in memory formation. ???: Regulates the autonomic nervous system via hormone production and release. Affects and regulates blood pressure, heart rate, hunger, thirst, sexual arousal, and the sleep/wake cycle ???: The "relay station" to the cerebral cortex

Limbic System Structures/Funct.  Amygdala: Involved in signaling the cortex of motivationally significant

stimuli such as those related to reward and fear in addition to social functions such as mating.  Hippocampus: Required for the formation of long-term memories  Parahippocampal gyrus: Plays a role in the formation of spatial memory and   



is part of the hippocampus Cingulate gyrus: Autonomic functions regulating heart rate, blood pressure and cognitive and attentional processing Fornix: Major white matter tract, carries signals from the hippocampus to the mammillary bodies and septal nuclei – involved in memory formation. Hypothalamus: Regulates the autonomic nervous system via hormone production and release. Affects and regulates blood pressure, heart rate, hunger, thirst, sexual arousal, and the sleep/wake cycle Thalamus: The "relay station" to the cerebral cortex

Limbic System Structures/Funct.  ???: Important for the formation of memory  ???: secretes hormones regulating homeostasis  ???: thought to contribute to new memories and to regulate

happiness.

 ??? cortex and ???: Receive smell input in the olfactory system.  ???: Region encompassing the cingulate, hippocampus, and

parahippocampal gyrus

 ???: Olfactory sensory input  ???: Involved in reward, pleasure, and addiction  ???: Required for decision making

Limbic System Structures/Funct.  Mammillary body: Important for the formation of memory  Pituitary gland: secretes hormones regulating homeostasis  Dentate gyrus: thought to contribute to new memories and to

regulate happiness.

 Entorhinal cortex and piriform cortex: Receive smell input in the

olfactory system.

 Fornicate gyrus: Region encompassing the cingulate,

hippocampus, and parahippocampal gyrus

 Olfactory bulb: Olfactory sensory input  Nucleus accumbens: Involved in reward, pleasure, and addiction  Orbitofrontal cortex: Required for decision making