Diencephalon Basal ganglia Internal capsule

By: Dr. Atal

DiencephalonEpithalamus Thalamus Hypothalamus Subthalamus

*metathalamus medial geniculate body lateral geniculate body

epithalamus

Pineal body Habenular nuclie Stria medullaris Taenia thalami

thalamus

Nuclear groups( IML) anterior anterior tubercle medial dorsomedial lateral ventral nuclear mass ventral anterior ventral lateral ventral posterior vpln vpmn lateral nuclear mass pulvinar lateral posterior *centromedian n. intralaminar n.

Specific Relay Nuclei (and Function) Their cortical connections are given at this point for information ( symbolizes a connection in both directions). VA ventral anterior (motor) premotor area and supplementary motor area VL ventral lateral (motor) precentral gyrus and premotor area VPL ventral posterolateral (somatosensory) postcentral gyrus VPM ventral posteromedial (trigeminal) postcentral gyrus MGB medial geniculate (body) nucleus (audi- tory) temporal cortex LGB 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 dorsomedial nucleus prefrontal cortex AN anterior nucleus limbic lobe Pul pulvinar visual cortex LP lateral posterior parietal lobe LD lateral dorsal parietal lobe

Nonspecific Nuclei (to Widespread Areas of the Cerebral Cortex) IL intralaminar CM centromedian Ret reticular

Lesions of the Thalamus

Sensory Loss

Result from thrombosis or hemorrhage damage to VPLN and VPMN loss of all forms of sensation

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Thalamic Syndrome May occur as the patient is recovering from a thalamic infarct spontaneous pain which is often excessive and unpleasant occurs on the opposite side of the body painful sensation may be aroused by light touch or cold may fail to respond to powerful analgesic drugs

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hypothalamus

Central control of : visceral autonomic endocrine functions effective behavior

Hypothalamic areas

I. Preoptic region preoptic n . A. supraoptic supraoptic paraventricular B. tuberal region ventromedial dorsomedial arcuate/infundibular posterior hypothalamic C.mamillary region mamillary nucleus posterior hypothalamic

II. Lateral hypothalamic area Bounded medially: mamillothalamic tract anterior column of fornix Bounded laterally: subthalamic region internal capsule

Clinical disorders associated with hypothalamic lesionsobesity and wasting sexual disorders hyperthermia and hypothermia diabetes insipidus disturbances of sleep emotional disorders

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subthalamus

Ventral to thalamus Medial to internal capsule Caudal to hypothalamus Closely associated with the basal ganglia in function

subthalamus

Zona incerta- between incertalenticular fasciculus and thalamic fasciculus *rostral continuation of midbrain reticular formation Forels tegmental field-includes fieldthe prerubral field Subthalamic nucleus *continous at the substantia nigra at its caudal extent *medial border of internal capsule

lesions of the subthalamic nucleus Hemiballismus

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Basal ganglia

Basal gangliaA. corpus striatum somatic motor function

B. amygdaloid nuclear complex regarded as a component of the limbic system olfactory input archistriatum beneath the uncus in the temporal lobe reciprocal connections with the hypothalamus and prepyriform cortex

Corpus striatum

1. neostriatum a. caudate nucleus b. putamen 2. paleosriatum a. globus pallidus * Lentiform nucleus putamen and globus pallidus

Caudate nucleusC shaped cellular mass Related throughout its extent to the lateral ventricle Head rostral to the thalamus Body arches along the dorsolateral border of the thalamus Tail lies in the roof of the inferior horn of the lateral ventricle

putamen

Largest and most lateral portion of the corpus striatum Between the external capsule and the lateral medullary lamina of the globus pallidus

striatumHigh concentrations of dopamine Contains glutamate conveyed by corticostriate fibers Serotonin transmitted from the raphe nuclei of the midbrain Striated efferent neurons contains GABA and substance P.

Globus pallidus

Medial to the putamen Medial medullary lamina divides globus pallidus into medial and lateral segments

claustrum

Narrow streak of gray matter between the lentiform nucleus and nuclear cortex Seperated by two white lamina: A. external capsule medially B. extreme capsule laterally

Amygdaloid nuclear complex

Dorsomedial portion of the temporal lobe Continous with the uncus of the parahippocampal gyrus

Internal capsule

Medially thalamus and caudate Laterally nucleus lentiform

Internal capsule

Anterior limb: a. anterior thalamic radiations b. prefrontal corticopontine tract Genu a. corticobulbar b. corticoreticular Posterior limb a. corticospinal b. frontopontine fibers c. superior thalamic radiation d. corticotectal, corticorubral, corticoreticular

Basal ganglia lesions

Extrapyramidal lesions

Parkinsons Chorea Athetosis Hemiballismus

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