Diencephalon,Basal Ganglia,Limbic System

8/7/2019 Diencephalon,Basal Ganglia,Limbic System

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DiencephalonDiencephalonBasal gangliaBasal ganglia

Internal capsuleInternal capsule

By: Dr. AtalBy: Dr. Atal



DiencephalonDiencephalon

EpithalamusEpithalamus

ThalamusThalamus

HypothalamusHypothalamus SubthalamusSubthalamus

*metathalamus*metathalamus medial geniculate bodymedial geniculate body

lateral geniculate bodylateral geniculate body





epithalamusepithalamus

Pineal bodyPineal body

Habenular nuclieHabenular nuclie

Stria medullarisStria medullaris Taenia thalamiTaenia thalami





thalamusthalamus

Nuclear groups( IML)Nuclear groups( IML)

anterioranterior

anterior tubercleanterior tubercle

medialmedial

dorsomedialdorsomedial laterallateral

ventral nuclear massventral nuclear mass

ventral anteriorventral anterior

ventral lateralventral lateral

ventral posteriorventral posterior

vplnvpln

vpmnvpmn

lateral nuclear masslateral nuclear mass

pulvinarpulvinar

lateral posteriorlateral posterior

*centromedian n.*centromedian n. intralaminarintralaminarn.n.



Specific Relay Nuclei (and Function)

Their cortical connections are given at this point for infor-mation (<---> symbolizes a connection in both directions).

VA ² ventral anterior (motor) <---> premotor area and

supplementary motor area

VL ² ventral lateral (motor) <---> precentral gyrus and

premotor area

VPL ²

ventral posterolateral (somatosensory) <- --> postcentral gyrus

VPM ² ventral posteromedial (trigeminal) <--->

postcentral gyrus

MGB ² medial geniculate (body) nucleus (audi- tory) <---

> temporal cortex

LGB ²

lateral geniculate (body) nucleus (vision) <--->occipital cortex



Association Nuclei (and

Association Cortex)

These nuclei are reciprocally

connected to association areas

of the cerebral cortex.

DM ² dorsomedial nucleus <-

--> prefrontal cortex AN ²

anterior nucleus <---> limbic

lobePul ² pulvinar <---> visual

cortex

LP ² lateral posterior <--->

parietal lobe

LD ² lateral dorsal <--->

parietal lobe



Nonspecific Nuclei (to

Widespread Areas of the

Cerebral Cortex)

IL ² intralaminar

CM ² centromedian

Ret ² reticular









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Lesions of the ThalamusLesions of the Thalamus

Sensory LossSensory Loss

Result from thrombosis or hemorrhageResult from thrombosis or hemorrhage damage to VPLN and VPMNdamage to VPLN and VPMN

loss of all forms of sensationloss of all forms of sensation

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Thalamic SyndromeThalamic Syndrome

May occur as the patient is recoveringMay occur as the patient is recovering

from a thalamic infarct from a thalamic infarct spontaneous pain which is oftenspontaneous pain which is often

excessive and unpleasant occurs on theexcessive and unpleasant occurs on theopposite side of the bodyopposite side of the body

painful sensation may be aroused by light painful sensation may be aroused by light touch or coldtouch or cold

may fail to respond to powerful analgesicmay fail to respond to powerful analgesicdru sdru s

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hypothalamushypothalamus

Central control of :Central control of :

visceral autonomicvisceral autonomic endocrine functionsendocrine functions

effective behavioreffective behavior















Hypothalamic areasHypothalamic areas

I. Preoptic regionI. Preoptic region

preoptic n .preoptic n .

A. supraoptic A. supraoptic

supraopticsupraoptic paraventricularparaventricular

B. tuberal regionB. tuberal region

ventromedialventromedial

dorsomedialdorsomedialarcuate/infundibulararcuate/infundibular

posterior hypothalamicposterior hypothalamic

C.mamillary regionC.mamillary region

mamillary nucleusmamillary nucleus

posterior hypothalamicposterior hypothalamic



II. Lateral hypothalamicII. Lateral hypothalamicareaarea

Bounded medially:Bounded medially: mamillothalamic tract mamillothalamic tract

anterior column of fornixanterior column of fornix

Bounded laterally:Bounded laterally:

subthalamic regionsubthalamic region

internal capsuleinternal capsule



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Clinical disorders associatedClinical disorders associated

with hypothalamic lesionswith hypothalamic lesions obesity and wastingobesity and wasting

sexual disorderssexual disorders

hyperthermia and hypothermiahyperthermia and hypothermia diabetes insipidusdiabetes insipidus

disturbances of sleepdisturbances of sleep

emotional disordersemotional disorders

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subthalamussubthalamus

Ventral to thalamus Ventral to thalamus

Medial to internalMedial to internalcapsulecapsule

Caudal toCaudal tohypothalamushypothalamus

Closely associatedClosely associated

with the basal gangliawith the basal ganglia in functionin function



subthalamussubthalamus

Zona incertaZona incerta-- betweenbetweenlenticular fasciculus andlenticular fasciculus andthalamic fasciculusthalamic fasciculus

*rostral continuation of *rostral continuation of midbrain reticular formationmidbrain reticular formation

Forels tegmental fieldForels tegmental field--includesincludesthe prerubral fieldthe prerubral field

Subthalamic nucleusSubthalamic nucleus *continous at the substantia*continous at the substantia

nigra at its caudal extent nigra at its caudal extent

*medial border of internal*medial border of internalcapsulecapsule





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lesions of the subthalamic nucleuslesions of the subthalamic nucleus

HemiballismusHemiballismus

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Basal gangliaBasal ganglia





Basal gangliaBasal ganglia

A. corpus striatum A. corpus striatum

somatic motor functionsomatic motor function

B. amygdaloid nuclear complexB. amygdaloid nuclear complex regarded as a component of the limbic systemregarded as a component of the limbic system

olfactory input olfactory input

archistriatumarchistriatum

beneath the uncus in the temporal lobebeneath the uncus in the temporal lobe reciprocal connections with the hypothalamusreciprocal connections with the hypothalamus

and prepyriform cortexand prepyriform cortex



Corpus striatumCorpus striatum

1. neostriatum1. neostriatum

a. caudate nucleusa. caudate nucleus

b. putamenb. putamen

2. paleosriatum2. paleosriatum

a. globus pallidusa. globus pallidus

* Lentiform nucleus* Lentiform nucleus

putamen and globusputamen and globus

palliduspallidus



Caudate nucleusCaudate nucleus

CC shaped cellular massshaped cellular mass

Related throughout its extent to theRelated throughout its extent to the

lateral ventriclelateral ventricle HeadHead rostral to the thalamusrostral to the thalamus

BodyBody arches along the dorsolateralarches along the dorsolateral

border of the thalamusborder of the thalamus TailTail lies in the roof of the inferior hornlies in the roof of the inferior horn

of the lateral ventricleof the lateral ventricle



putamenputamen

Largest and most lateral portion of theLargest and most lateral portion of thecorpus striatumcorpus striatum

Between the external capsule and theBetween the external capsule and thelateral medullary lamina of the globuslateral medullary lamina of the globuspalliduspallidus



striatumstriatum

High concentrations of dopamineHigh concentrations of dopamine

Contains glutamate conveyed byContains glutamate conveyed by

corticostriate fiberscorticostriate fibers Serotonin transmitted from the rapheSerotonin transmitted from the raphe

nuclei of the midbrainnuclei of the midbrain

Striated efferent neurons contains GABAStriated efferent neurons contains GABAand substance P.and substance P.



Globus pallidusGlobus pallidus

Medial to the putamenMedial to the putamen

Medial medullary lamina divides globusMedial medullary lamina divides globuspallidus into medial and lateral segmentspallidus into medial and lateral segments



claustrumclaustrum

Narrow streak of grayNarrow streak of graymatter between thematter between thelentiform nucleus andlentiform nucleus andnuclear cortexnuclear cortex

Seperated by two whiteSeperated by two whitelamina:lamina:

A. external capsule A. external capsulemediallymedially

B. extreme capsuleB. extreme capsulelaterallylaterally



Amygdaloid nuclear complex Amygdaloid nuclear complex

Dorsomedial portionDorsomedial portionof the temporal lobeof the temporal lobe

Continous with theContinous with theuncus of theuncus of theparahippocampalparahippocampalgyrusgyrus




MediallyMedially thalamusthalamusand caudateand caudate

LaterallyLaterally lentiformlentiformnucleusnucleus






Anterior limb: Anterior limb:

a. anterior thalamic radiationsa. anterior thalamic radiations

b. prefrontal corticopontine tract b. prefrontal corticopontine tract

GenuGenu

a. corticobulbara. corticobulbar

b. corticoreticularb. corticoreticular

Posterior limbPosterior limb

a. corticospinala. corticospinal

b. frontopontine fibersb. frontopontine fibers

c. superior thalamic radiationc. superior thalamic radiation

d. corticotectal, corticorubral,d. corticotectal, corticorubral,

corticoreticularcorticoreticular



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Basal ganglia lesionsBasal ganglia lesions

Extrapyramidal lesionsExtrapyramidal lesions

ParkinsonsParkinsons ChoreaChorea

Athetosis Athetosis

HemiballismusHemiballismus

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Limbic systemLimbic systemMemory and behaviorMemory and behavior



Limbic lobeLimbic lobe

Cingulate gyrusCingulate gyrus

anterior extensionanterior extension septal regionseptal region

A. paraterminal A. paraterminal B. subcallosal gyrusB. subcallosal gyrus

Parahippocampal gyrus (temporal lobe)Parahippocampal gyrus (temporal lobe) neocortexneocortex





Limbic systemLimbic system

Limbic lobe connections to otherLimbic lobe connections to otherstructuresstructures

hippocampal formation (posterior part hippocampal formation (posterior part of the parahippocampal gyrusof the parahippocampal gyrus

amygdala / amygdaloid nucleus (amygdala / amygdaloid nucleus (anterior part of the parahippocampalanterior part of the parahippocampalgyrus)gyrus)



Hippocampal formationHippocampal formation

Memory and learningMemory and learning

3 parts3 parts

A. dentate gyrus A. dentate gyrus

B. hippocampus properB. hippocampus proper

C. subiculumC. subiculum transition between hippocampus propertransition between hippocampus properand entorhinal area (part of the parahippocampal gyrus)and entorhinal area (part of the parahippocampal gyrus)

A and B A and B archicortexarchicortex

Parahippocampal gyrusParahippocampal gyrus -- neocortexneocortex




Initial center in a reverberating pathway called the PAPEZ circuit Initial center in a reverberating pathway called the PAPEZ circuit

Inputs from prefrontal cortex , posterior parietal , temporal lobeInputs from prefrontal cortex , posterior parietal , temporal lobe

CingulumCingulum

Entorhinal part of parahippocampal gyrusEntorhinal part of parahippocampal gyrus

HippocampusHippocampus

FornixFornix

fimbriaefimbriae

crus of fornixcrus of fornix

hippocampal commissurehippocampal commissure

body of fornixbody of fornix

column of fornixcolumn of fornix Anterior commissure Anterior commissure

pre commissural fiberspre commissural fibers from hippocampus to septal area and forebrainfrom hippocampus to septal area and forebrainstructuresstructures

post commissural fiberspost commissural fibers-- mamillary bodymamillary body mamilothalamic tract mamilothalamic tract

anterior thalamic nucleusanterior thalamic nucleus thalamocingulate radiationthalamocingulate radiation

cingulate gyruscingulate gyrus-- cingulumcingulum






Bilateral removal for tx for epilepsyBilateral removal for tx for epilepsy

Profound loss of recent or short term memoryProfound loss of recent or short term memory(anterograde amnesia)(anterograde amnesia)

Loss of ability to learnLoss of ability to learn

Memories of the distant past and intelligenceMemories of the distant past and intelligenceremain intact remain intact

Alzheimer disease Alzheimer disease loss of neurons in theloss of neurons in thehippocampal formation and reduction of hippocampal formation and reduction of cholinergic innervation of the cerebral cortexcholinergic innervation of the cerebral cortex



Limbic system syndromesLimbic system syndromes

Alzheimer Alzheimer loss of recent memoryloss of recent memory

KluverKluver-- BucyBucy --behavioral changesbehavioral changes

Korsakoff Korsakoff loss of recent memory andloss of recent memory andconfabulation (fabricate false accounts of confabulation (fabricate false accounts of recent events)recent events)



Amygdaloid nucleus Amygdaloid nucleus

BehaviorBehavior

EmotionsEmotions

Located beneath the uncus near theLocated beneath the uncus near thedosomedial tip of the temporal lobedosomedial tip of the temporal lobe

Connections to the olfactory striaeConnections to the olfactory striae



Alzheimers disease Alzheimers disease

progressive dementia (<65)progressive dementia (<65)

senile dementia (>65)senile dementia (>65)

increasingly forgetfulincreasingly forgetful abnormalities in memory, cognition, orientation and behaviourabnormalities in memory, cognition, orientation and behaviour

loss of neurons in the hippocampal formation and adjacent loss of neurons in the hippocampal formation and adjacent

parahippocampal cortexparahippocampal cortex

reduction in cholinergic enervation of the cerebral cortexreduction in cholinergic enervation of the cerebral cortex

results in denervation of basal nucleus of MEYNERT located in theresults in denervation of basal nucleus of MEYNERT located in theanterior perforated substance commonly referred to asanterior perforated substance commonly referred to asSUBSTANTIA INNOMINATA.SUBSTANTIA INNOMINATA.



Korsakoff syndrome or PsychosisKorsakoff syndrome or Psychosis

loss of recent memory and a tendency toloss of recent memory and a tendency tofabricate false accounts of recent eventsfabricate false accounts of recent events

medial parts of the medial dorsalmedial parts of the medial dorsalthalamic nuclei ( Lesion)thalamic nuclei ( Lesion)



KluverKluver Bucy syndromeBucy syndrome

behavioral changes:behavioral changes:

-- absence of emotional response to fear, rageabsence of emotional response to fear, rageand aggression cease to exist and aggression cease to exist

-- compulsion to be overly attentive, to allcompulsion to be overly attentive, to allsensory stimulisensory stimuli

-- hypersexualityhypersexuality -- psychic blindness or visual agnosiapsychic blindness or visual agnosia

-- damage to amygdaloid nucleusdamage to amygdaloid nucleus



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Diencephalon,Basal Ganglia,Limbic System