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Home , Diencephalon, Lenticular fasciculus, Subthalamus, Ventral anterior nucleus, Ventral nuclear group

Diencephalon

•  dorsal thalamus

• • habenular nucleus and commissure •  ventral thalamus (STN) field of Forel Diencephalon

dorsal surface Diencephalon

ventral surface Diencephalon Medial Surface THALAMUS Function of the Thalamus

• Sensory relay – ALL sensory information (except smell) • Motor integration – Input from cortex, and • Arousal – Part of reticular activating system • modulation – All nociceptive information • Memory & behavior – Lesions are disruptive Classification of Thalamic Nuclei

I. Lateral Nuclear Group II. Medial Nuclear Group III. Anterior Nuclear Group IV. Posterior Nuclear Group V. Metathalamic Nuclear Group VI. Intralaminar Nuclear Group VII. Thalamic Reticular Nucleus Classification of Thalamic Nuclei LATERAL NUCLEAR GROUP

Ventral Nuclear Group Ventral Posterior Nucleus (VP) ventral posterolateral nucleus (VPL) ventral posteromedial nucleus (VPM)

Input to the Thalamus

Sensory relay - Ventral posterior group all sensation from body and head, including pain Projections from the Thalamus

Sensory relay Ventral posterior group

all sensation from body and head, including pain LATERAL NUCLEAR GROUP

Ventral Lateral Nucleus

Ventral Anterior Nucleus

Input to the Thalamus

Motor control and integration Projections from the Thalamus

Motor control and integration LATERAL NUCLEAR GROUP

Prefrontal SMA MI, PM SI

SNr TTT GPi Cbll ML, STT Lateral Dorsal Nuclear Group Lateral Dorsal Nucleus Lateral Posterior Nucleus Pulvinar LATERAL NUCLEAR GROUP

cingulate gyrus, Somesthetic precuneus Association Visual Area Association area

HF SC, Pretectal MEDIAL NUCLEAR GROUP

Dorsomedial Nucleus (MD) - pars magnocellularis - pars parvocellularis Midline Nuclear Group

Input to the Thalamus

Behavior and connection with hypothalamus Projections from the Thalamus

Behavior and emotion connection with hypothalamus MEDIAL & ANTERIOR NUCLEAR GROUP

Prefrontal Frontal MB, HF Cortex Eye Field Medial Frontal Gyrus

cingulate gyrus Basal SNr, SC, RF METATHALAMIC NUCLEAR GROUP

Medial Geniculate Nucleus (MG) ventral nucleus dorsal nucleus medial nucleus

Lateral Geniculate Nucleus (LG) dorsal nucleus ventral nucleus Input to the Thalamus

Metathalamus Vision and Hearing Projections from the Thalamus

Metathalamus Vision and Hearing INTRALAMINAR NUCLEAR GROUP

Rostral Intralaminar Nuclei central lateral nucleus, central medial nucleus, paracentral nucleus,

Caudal Intralaminar Nuclei centro-median nucleus THALAMIC RETICULAR NUCLEUS

Cerebral Cortex

Thalamic Thalamocortical Reticular Neuron Nucleus

Subcortical Structure Summary of Thalamic Connectivity

I. Sensory Input general sensation special sensation taste, equilibrium, hearing, vision II. Motor Input cerebellum, basal ganglia III. IV. mammillary nucleus Sensory Input

(1) General Sensation 1. Medial - VPL 2. - VPL 3. Trigeminothalamic tract – VPM (2) Taste sensation - VPM (3) Sense of equilibrium - VPL (4) Auditory sensation - MG (5) Vision - LG

Motor Input

(1) Cerebellum VL, VPL,

(2) Basal ganglia 1. GPi 2. SNr Reticular Formation & Limbic System

Reticular formation rostral intralaminar nuclei thalamic reticular nucleus

Limbic System - AN Hippocampal Formation - AN

Clinical Syndromes of the Thalamus

Posterolateral thalamic syndromes sensory disorders Thalamic (Dejerine-Roussy) syndrome ----- VP nucleus - pain

Medial thalamic syndromes disorders of consciousness thalamic neglect, thalamic amnesia, akinetic mutism

Anterolateral thalamic syndromes motor disorders paresis, ataxia, motor incoordination, dysphagia Thalamic (Dejerine-Roussy) Syndrome

Joseph Jules Dejerine Gustave Roussy (1849-1917) (1874-1948) Epithalamus  Limbic System

Habenular Nucleus

Medial Habenular Nucleus

Lateral Habenular Nucleus

Habenular Commissure

Pineal Gland Epithalamus

 Corpus pineale

 Trigonum & commissura habenulae

 Stria medullaris thalami

 Commissura posterior

 Tela choroidea & plexus choroideus of 3rd ventricle Epithalamus

1. Trigonum habenulae Small nuclei habenulae, above commissura posterior. 3 connections: – Stria medullaris thalami – afferents to nuclei habenulae mainly from area septalis – Commissura habenularum – btwn trigonum habenulae – Tractus habenulointerpeduncularis (fasciculus retroflexus) – efferents to nucl. interpeduncularis, RF, substantia grisea centralis

2. Functions of nuclei habenulae Vague. Supposed to mediate olfactory stimuli and feeding behavior. Connect olfactory , hypothalamus and limbic system with brain stem. 3. Corpus pineale Produces melatonin and serotonin. Controls circadian rhythms, reprductive cycles and maturation (puberty) Subthalamus  Basal Ganglia

Subthalamic nucleus Field of Forel H H1 thalamic fasciculus H2