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Diencephalon
Diencephalon
• Thalamus dorsal thalamus
• Hypothalamus
pituitary gland
• Epithalamus
habenular nucleus and commissure
pineal gland
• Subthalamus ventral thalamus
subthalamic nucleus (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, cerebellum
and basal ganglia
• Arousal – Part of reticular activating
system
• Pain 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
Ventral Nuclear Group
TTT
ML, STT Cbll GPi
SNr
Prefrontal SMA MI, PM SI
Lateral Dorsal Nuclear Group
Lateral Dorsal Nucleus
Lateral Posterior Nucleus
Pulvinar
LATERAL NUCLEAR GROUP
SC, Pretectal
HF
Visual
Association
area
Somesthetic
Association
Area
cingulate gyrus,
precuneus
MEDIAL NUCLEAR GROUP
Dorsomedial Nucleus (MD) - pars magnocellularis - pars parvocellularis
Midline Nuclear Group
Input to the Thalamus
Behavior and emotion connection with hypothalamus
Projections from the Thalamus
Behavior and emotion connection with hypothalamus
MEDIAL & ANTERIOR NUCLEAR GROUP
MB, HF
Prefrontal
Cortex Frontal
Eye Field Medial
Frontal
Gyrus
cingulate
gyrus Basal
forebrain 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
Subcortical Structure
Thalamic
Reticular
Nucleus
Thalamocortical
Neuron
Summary of Thalamic Connectivity
I. Sensory Input
general sensation
special sensation
taste, equilibrium, hearing, vision
II. Motor Input
cerebellum, basal ganglia
III. Reticular Formation
IV. Limbic System
mammillary nucleus
hippocampal formation
Sensory Input
(1) General Sensation
1. Medial lemniscus - VPL
2. Spinothalamic tract - 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
Mammillary Body - 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
(1849-1917)
Gustave Roussy
(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 brain,
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
zona incerta
Field of Forel
H ansa lenticularis
H1 thalamic fasciculus
H2 lenticular fasciculus