thalamic nuclei

Thalamus In Situ 138

Thalamic Nuclei 139

Thalamus in Horizontal Section 141

Thalamus in Coronal Section 142

CHAPTER 8

Thalamus

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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 andsubcortical 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 Due to its multiple functions, damage to the thalamus can cause many Significance problems, including sensory abnormalities, visual-field deficits, and behavioral

changes

Lesions to the sensory area can cause numbness on the contralateral body andface

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138 NETTER’S CONCISE NEUROANATOMY

Thalamus

THALAMUS IN SITU

Interventricular foramen

3rd ventricle

Choroid plexusInternal cerebral v. Superiorthalamostriate v.(vena teminalis)

Pes hippocampiInferior horn oflateral ventricle

Dentate gyrusCollateraleminence

HippocampusFimbria ofhippocampus

Posteriorcommissure Habenularcommissure

Pineal glandCollateraltrigone

Calcar avisPosterior hornof lateral ventricle

Calcarinesulcus (fissure)

Corpus callosum (cut)

Head of caudate nucleus

Septum pellucidum

Columns of fornix

Anterior tubercle

Stria terminalis

Interthalamic adhesion

Stria medullaris

Habenular tribone

Pulvinar (lifted)

Lateral geniculate body

Medial geniculate body

Brachium ofsuperior colliculus

Brachium ofinferior colliculus

Superior colliculus

Inferior colliculus

Cerebellum

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• The thalamus is composed of many nuclei, which have motor, sensory, and limbicconnections.

• Some nuclei are nonspecific in nature.

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NETTER’S CONCISE NEUROANATOMY 139

Thalamus

THALAMIC NUCLEI

NUCLEUS INPUT(S) OUTPUT(S) FUNCTION

Sensory Nuclei

Ventroposterolateral Spinothalamic tract Primary sensory Somatic sensation(VPL) Medial lemniscus cortex for contralateral

body

Ventroposteromedial Trigeminothalamic tract, Primary sensory Somatic sensation(VPM) pontine taste area cortex for contralateral

face, taste

Medial geniculate Brachium of the inferior Primary auditory Hearing(MGN) colliculus cortex

Lateral geniculate Optic tract Primary visual Vision(LGN) cortex

Pulvinar Lateral geniculate body Visual association Visual processing(LGB), medial geniculate cortexbody (MGB), superior andinferior colliculi

Motor Nuclei

Ventrolateral (VL) Cerebellum and basal Primary motor Modulation andganglia cortex coordination of

movement

Ventroanterior (VA) Basal ganglia Premotor cortex Initiation andplanning ofmovement

Ventrointermedial (VI) Cerebellum Primary motor Coordination ofcortex movement

Limbic and Nonspecific Projection Nuclei

Anterior (Ant) Mammillothalamic tract Cingulate cortex Memory storageand emotion

Mediodorsal (MD) Temporal lobe, amygdala, Prefrontal cortex Motivation, drive,hypothalamus emotion

Centromedian (CM) Slow pain pathways Nonspecific Emotional contentcortical of painprojections

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Thalamus

THALAMIC NUCLEI continued

Thalamocorticalradiations

Central sulcus

CM CentromedianLD Lateral dorsalLP Lateral posteriorMD Medial dorsalVA Ventral anteriorVI Ventral intermedialVL Ventral lateralVPL Ventral posterolateralVPM Ventral posteromedial

Anterior nuclei

From globus pallidusand substantia nigra

Reticular nucleus(pulled away)

Somesthetic from body(spinothalamic tract and medial lemniscus) Somesthetic from head (trigeminal nerve)

Optic tract

Lateral geniculate body

Acoustic pathway

Medial geniculate body

Pulvinar

Interthalamic adhesion

Midline (median) nuclei

Other medial nuclei

Intralaminar nuclei

Internal medullary lamina

MD

LDLP

VA

VLVI

VPLCM

VPM

Fromcerebellum

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• 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.

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Thalamus

THALAMUS IN HORIZONTAL SECTION

Frontal lobe

Head of caudate nucleus

Anterior limb ofinternal capsule

Genu of corpuscallosum

Globus pallidus

Putamen

External capsule

Claustrum

Extremecapsule

Genu ofinternalcapsule

Columnsof fornix

Anteriorhorn oflateralventricle

Thirdventricle

Insularcortex

Thalamus

Posterior limb ofinternal capsule

Auditory radiations

Pulvinar

Tail of caudate nucleusTemporal lobe

Opticradiation

Temporal pole oflateral ventricle

Choroid plexus

Fimbria of fornix

Occipital lobe

Splenium of thecorpus callosum

Level of section(head of caudate

and mid thalamus)

Transverse temporalgyrus of Heschl

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STRUCTURE ANATOMIC NOTES FUNCTIONAL SIGNIFICANCE

Thalamus Individual nuclei are anatomicallyseparated. The thalamus defines the borders of the 3rd ventricle

LGN of the Comma-shaped, lateral nucleus of Serves as the visual relay center from thalamus the thalamus the optic tract to occipital cortex.

Lesions can cause visual field defects

MGN of the Medial to the lateral geniculate Serves as the auditory relay center thalamus nucleus from the inferior colliculus to auditory

cortex

MDN of the Most dorsal and medial nucleus; Part of the limbic systemthalamus forms part of the wall of the 3rd

ventricle

CM thalamus Located ventral to the MDN Involved in the central modulation and perception of pain

Lateral Contains multiple nuclear structures, Involved in motor and sensory relaysthalamus including the VL and VPL

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Thalamus

THALAMUS IN CORONAL SECTION

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Thalamus

THALAMUS IN CORONAL SECTION continued

Level of section(midthalamus)

Body of corpus callosum

Cingulum

Cingulate cortex

Stria terminalisBody of caudatenucleus

Medial dorsal thalamus

Insular cortex

Lateral thalamus

Lateral geniculate nucleus

Centromedian thalamus

Tail of the caudate nucleus

Medialgeniculatenucleus

Hippocampalformation

Entorhinalcortex

Cortex ofcerebellum Superior

cerebellar peduncle

Pons (floor offourth ventricle)

Inferior cerebellarpeduncle

Medulla

Columns of fornixInterventricularforamen of Monro

Third ventricle

Body of lateralventricle

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thalamic nuclei

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