Thalamus
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CHAPTER 8
Thalamus
Thalamus In Situ
138
Thalamic Nuclei
139
Thalamus in Horizontal Section
141
Thalamus in Coronal Section
142
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Thalamus THALAMUS IN SITU
Location
Paired, medially placed, deep egg-shaped nuclear structures that form part of the lateral wall of the 3rd ventricle
Architecture
Composed of multiple nuclei, which receive input from many cortical and subcortical structures
Function
Functions as the “gateway to the cortex.” Sensory input, other than olfaction, relays through the thalamus before reaching the cortex. All output to the cortex from the cerebellum and basal ganglia relays through the thalamus. The thalamus also relays limbic input to the cortex
Clinical Significance
Due to its multiple functions, damage to the thalamus can cause many problems, including sensory abnormalities, visual-field deficits, and behavioral changes Lesions to the sensory area can cause numbness on the contralateral body and face
Interventricular foramen
Corpus callosum (cut) Head of caudate nucleus
3rd ventricle Choroid plexus Internal cerebral v. Superior thalamostriate v. (vena teminalis) Pes hippocampi Inferior horn of lateral ventricle Dentate gyrus Collateral eminence Hippocampus Fimbria of hippocampus
Septum pellucidum Columns of fornix Anterior tubercle Stria terminalis Interthalamic adhesion
Stria medullaris Habenular tribone Pulvinar (lifted) Lateral geniculate body Medial geniculate body Brachium of superior colliculus
Posterior commissure Habenular commissure Pineal gland Collateral trigone
Brachium of inferior colliculus Superior colliculus Inferior colliculus Cerebellum
Calcar avis Posterior horn of lateral ventricle Calcarine sulcus (fissure)
138 NETTER’S CONCISE NEUROANATOMY
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Thalamus THALAMIC NUCLEI
• The thalamus is composed of many nuclei, which have motor, sensory, and limbic connections. • Some nuclei are nonspecific in nature. NUCLEUS
INPUT(S)
OUTPUT(S)
FUNCTION
Sensory Nuclei Ventroposterolateral (VPL)
Spinothalamic tract Medial lemniscus
Primary sensory cortex
Somatic sensation for contralateral body
Ventroposteromedial (VPM)
Trigeminothalamic tract, pontine taste area
Primary sensory cortex
Somatic sensation for contralateral face, taste
Medial geniculate (MGN)
Brachium of the inferior colliculus
Primary auditory cortex
Hearing
Lateral geniculate (LGN)
Optic tract
Primary visual cortex
Vision
Pulvinar
Lateral geniculate body (LGB), medial geniculate body (MGB), superior and inferior colliculi
Visual association cortex
Visual processing
Motor Nuclei Ventrolateral (VL)
Cerebellum and basal ganglia
Primary motor cortex
Modulation and coordination of movement
Ventroanterior (VA)
Basal ganglia
Premotor cortex
Initiation and planning of movement
Ventrointermedial (VI)
Cerebellum
Primary motor cortex
Coordination of movement
Limbic and Nonspecific Projection Nuclei Anterior (Ant)
Mammillothalamic tract
Cingulate cortex
Memory storage and emotion
Mediodorsal (MD)
Temporal lobe, amygdala, hypothalamus
Prefrontal cortex
Motivation, drive, emotion
Centromedian (CM)
Slow pain pathways
Nonspecific cortical projections
Emotional content of pain
NETTER’S CONCISE NEUROANATOMY 139
8
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Thalamus THALAMIC NUCLEI
continued
Thalamocortical radiations
Central sulcus
CM LD LP MD VA VI VL VPL VPM
Centromedian Lateral dorsal Lateral posterior Medial dorsal Ventral anterior Ventral intermedial Ventral lateral Ventral posterolateral Ventral posteromedial
Internal medullary lamina Intralaminar nuclei
Anterior nuclei
Other medial nuclei Midline (median) nuclei
MD
Interthalamic adhesion LD LP
VA
Pulvinar
VL VI
CM
VPL
From globus pallidus and substantia nigra Reticular nucleus (pulled away)
Acoustic pathway From cerebellum
Somesthetic from body (spinothalamic tract and medial lemniscus)
140 NETTER’S CONCISE NEUROANATOMY
Medial geniculate body
VPM
Lateral geniculate body Optic tract Somesthetic from head (trigeminal nerve)
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Thalamus THALAMUS IN HORIZONTAL SECTION
• Thalami form the lateral walls of the third ventricle. • Posterior limb of the internal capsule separates thalamus from the lentiform nucleus. • Pulvinar is demonstrated in the artwork below.
Frontal lobe External capsule Anterior limb of internal capsule Claustrum Extreme capsule Level of section (head of caudate and mid thalamus)
Head of caudate nucleus Genu of corpus callosum Genu of internal capsule
Insular cortex
Anterior horn of lateral ventricle
Posterior limb of internal capsule Transverse temporal gyrus of Heschl Auditory radiations Tail of caudate nucleus Temporal lobe
Optic radiation Temporal pole of lateral ventricle Choroid plexus Fimbria of fornix Occipital lobe
Columns of fornix Third ventricle Globus pallidus Putamen Splenium of the corpus callosum Thalamus Pulvinar
NETTER’S CONCISE NEUROANATOMY 141
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Thalamus THALAMUS IN CORONAL SECTION
STRUCTURE
ANATOMIC NOTES
FUNCTIONAL SIGNIFICANCE
Thalamus
Individual nuclei are anatomically separated. The thalamus defines the borders of the 3rd ventricle
LGN of the thalamus
Comma-shaped, lateral nucleus of the thalamus
Serves as the visual relay center from the optic tract to occipital cortex. Lesions can cause visual field defects
MGN of the thalamus
Medial to the lateral geniculate nucleus
Serves as the auditory relay center from the inferior colliculus to auditory cortex
MDN of the thalamus
Most dorsal and medial nucleus; forms part of the wall of the 3rd ventricle
Part of the limbic system
CM thalamus
Located ventral to the MDN
Involved in the central modulation and perception of pain
Lateral thalamus
Contains multiple nuclear structures, including the VL and VPL
Involved in motor and sensory relays
142 NETTER’S CONCISE NEUROANATOMY
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Thalamus THALAMUS IN CORONAL SECTION
continued
Body of corpus callosum Cingulate cortex Interventricular foramen of Monro
Columns of fornix Third ventricle Body of lateral ventricle
Cingulum Stria terminalis Body of caudate nucleus
Level of section (midthalamus) Medial dorsal thalamus Insular cortex Lateral thalamus Lateral geniculate nucleus Centromedian thalamus Tail of the caudate nucleus
Hippocampal formation Medial geniculate nucleus Cortex of cerebellum Entorhinal cortex
Superior cerebellar peduncle Pons (floor of fourth ventricle) Inferior cerebellar peduncle Medulla
NETTER’S CONCISE NEUROANATOMY 143
8
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CHAPTER 8
Thalamus
Thalamus In Situ
138
Thalamic Nuclei
139
Thalamus in Horizontal Section
141
Thalamus in Coronal Section
142
Ch008_NC22.qxd 16/12/06 3:08 PM Page 138
8
Thalamus THALAMUS IN SITU
Location
Paired, medially placed, deep egg-shaped nuclear structures that form part of the lateral wall of the 3rd ventricle
Architecture
Composed of multiple nuclei, which receive input from many cortical and subcortical structures
Function
Functions as the “gateway to the cortex.” Sensory input, other than olfaction, relays through the thalamus before reaching the cortex. All output to the cortex from the cerebellum and basal ganglia relays through the thalamus. The thalamus also relays limbic input to the cortex
Clinical Significance
Due to its multiple functions, damage to the thalamus can cause many problems, including sensory abnormalities, visual-field deficits, and behavioral changes Lesions to the sensory area can cause numbness on the contralateral body and face
Interventricular foramen
Corpus callosum (cut) Head of caudate nucleus
3rd ventricle Choroid plexus Internal cerebral v. Superior thalamostriate v. (vena teminalis) Pes hippocampi Inferior horn of lateral ventricle Dentate gyrus Collateral eminence Hippocampus Fimbria of hippocampus
Septum pellucidum Columns of fornix Anterior tubercle Stria terminalis Interthalamic adhesion
Stria medullaris Habenular tribone Pulvinar (lifted) Lateral geniculate body Medial geniculate body Brachium of superior colliculus
Posterior commissure Habenular commissure Pineal gland Collateral trigone
Brachium of inferior colliculus Superior colliculus Inferior colliculus Cerebellum
Calcar avis Posterior horn of lateral ventricle Calcarine sulcus (fissure)
138 NETTER’S CONCISE NEUROANATOMY
Ch008_NC22.qxd 16/12/06 3:08 PM Page 139
Thalamus THALAMIC NUCLEI
• The thalamus is composed of many nuclei, which have motor, sensory, and limbic connections. • Some nuclei are nonspecific in nature. NUCLEUS
INPUT(S)
OUTPUT(S)
FUNCTION
Sensory Nuclei Ventroposterolateral (VPL)
Spinothalamic tract Medial lemniscus
Primary sensory cortex
Somatic sensation for contralateral body
Ventroposteromedial (VPM)
Trigeminothalamic tract, pontine taste area
Primary sensory cortex
Somatic sensation for contralateral face, taste
Medial geniculate (MGN)
Brachium of the inferior colliculus
Primary auditory cortex
Hearing
Lateral geniculate (LGN)
Optic tract
Primary visual cortex
Vision
Pulvinar
Lateral geniculate body (LGB), medial geniculate body (MGB), superior and inferior colliculi
Visual association cortex
Visual processing
Motor Nuclei Ventrolateral (VL)
Cerebellum and basal ganglia
Primary motor cortex
Modulation and coordination of movement
Ventroanterior (VA)
Basal ganglia
Premotor cortex
Initiation and planning of movement
Ventrointermedial (VI)
Cerebellum
Primary motor cortex
Coordination of movement
Limbic and Nonspecific Projection Nuclei Anterior (Ant)
Mammillothalamic tract
Cingulate cortex
Memory storage and emotion
Mediodorsal (MD)
Temporal lobe, amygdala, hypothalamus
Prefrontal cortex
Motivation, drive, emotion
Centromedian (CM)
Slow pain pathways
Nonspecific cortical projections
Emotional content of pain
NETTER’S CONCISE NEUROANATOMY 139
8
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8
Thalamus THALAMIC NUCLEI
continued
Thalamocortical radiations
Central sulcus
CM LD LP MD VA VI VL VPL VPM
Centromedian Lateral dorsal Lateral posterior Medial dorsal Ventral anterior Ventral intermedial Ventral lateral Ventral posterolateral Ventral posteromedial
Internal medullary lamina Intralaminar nuclei
Anterior nuclei
Other medial nuclei Midline (median) nuclei
MD
Interthalamic adhesion LD LP
VA
Pulvinar
VL VI
CM
VPL
From globus pallidus and substantia nigra Reticular nucleus (pulled away)
Acoustic pathway From cerebellum
Somesthetic from body (spinothalamic tract and medial lemniscus)
140 NETTER’S CONCISE NEUROANATOMY
Medial geniculate body
VPM
Lateral geniculate body Optic tract Somesthetic from head (trigeminal nerve)
Ch008_NC22.qxd 16/12/06 3:08 PM Page 141
Thalamus THALAMUS IN HORIZONTAL SECTION
• Thalami form the lateral walls of the third ventricle. • Posterior limb of the internal capsule separates thalamus from the lentiform nucleus. • Pulvinar is demonstrated in the artwork below.
Frontal lobe External capsule Anterior limb of internal capsule Claustrum Extreme capsule Level of section (head of caudate and mid thalamus)
Head of caudate nucleus Genu of corpus callosum Genu of internal capsule
Insular cortex
Anterior horn of lateral ventricle
Posterior limb of internal capsule Transverse temporal gyrus of Heschl Auditory radiations Tail of caudate nucleus Temporal lobe
Optic radiation Temporal pole of lateral ventricle Choroid plexus Fimbria of fornix Occipital lobe
Columns of fornix Third ventricle Globus pallidus Putamen Splenium of the corpus callosum Thalamus Pulvinar
NETTER’S CONCISE NEUROANATOMY 141
8
Ch008_NC22.qxd 16/12/06 3:08 PM Page 142
8
Thalamus THALAMUS IN CORONAL SECTION
STRUCTURE
ANATOMIC NOTES
FUNCTIONAL SIGNIFICANCE
Thalamus
Individual nuclei are anatomically separated. The thalamus defines the borders of the 3rd ventricle
LGN of the thalamus
Comma-shaped, lateral nucleus of the thalamus
Serves as the visual relay center from the optic tract to occipital cortex. Lesions can cause visual field defects
MGN of the thalamus
Medial to the lateral geniculate nucleus
Serves as the auditory relay center from the inferior colliculus to auditory cortex
MDN of the thalamus
Most dorsal and medial nucleus; forms part of the wall of the 3rd ventricle
Part of the limbic system
CM thalamus
Located ventral to the MDN
Involved in the central modulation and perception of pain
Lateral thalamus
Contains multiple nuclear structures, including the VL and VPL
Involved in motor and sensory relays
142 NETTER’S CONCISE NEUROANATOMY
Ch008_NC22.qxd 16/12/06 3:08 PM Page 143
Thalamus THALAMUS IN CORONAL SECTION
continued
Body of corpus callosum Cingulate cortex Interventricular foramen of Monro
Columns of fornix Third ventricle Body of lateral ventricle
Cingulum Stria terminalis Body of caudate nucleus
Level of section (midthalamus) Medial dorsal thalamus Insular cortex Lateral thalamus Lateral geniculate nucleus Centromedian thalamus Tail of the caudate nucleus
Hippocampal formation Medial geniculate nucleus Cortex of cerebellum Entorhinal cortex
Superior cerebellar peduncle Pons (floor of fourth ventricle) Inferior cerebellar peduncle Medulla
NETTER’S CONCISE NEUROANATOMY 143
8
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