BRS

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BRS Neuroanatomy

■ contains three subnuclei : a. Ventral posterolateral (VPL) nucleus

■ receives the spinothalamic tracts and the medial lemniscus. ■ projects to the somesthetic (sensory) cortex (areas 3, 1, and 2). ■ lesion results in contralateral loss of pain and temperature sensation as well as loss of tactile discrimination in the trunk and extremities.

b. Ventral posteromedial (VPM) nucleus ■ receives the trigeminothalamic tracts.

■ receives taste from the solitary and parabrachial nuclei. ■ projects to the somesthetic cortex (areas 3, 1, and 2). ■ lesion results in contralateral loss of pain and temperature sensation, and loss of tactile discrimination in the head; results in ipsilateral loss of taste. c. Ventral posteroinferior nucleus

■ receives vestibulothalamic fibers from the vestibular nuclei. ■ projects to the vestibular area of the somesthetic cortex.

F. Lateral geniculate body (LGB) ■ a visual relay nucleus. ■ receives retinal input via the optic tract. ■ projects to the primary visual cortex (area 17, the lingual gyrus, and the cuneus) via the optic (retrolenticular) radiations.

G. Medial geniculate body

■ an auditory relay nucleus. ■ receives auditory input via the brachium of the inferior colliculus. ■ projects to the primary auditory cortex (areas 41 and 42) via the auditory (sublenticular) radiations.

IV. BLOOD SUPPLY OF THE THALAMUS

A. Posterior communicating artery ■ gives rise to the anterior thalamoperforating arteries. B. Posterior cerebral artery ■ gives rise to the posterior choroidal arteries. ■ gives rise to the posterior thalamoperforating arteries.

C. Anterior choroidal artery

■ primarily serves the LGB.

V. INTERNAL CAPSULE (Figure 13.3)

■ a layer of white matter (myelinated axons) that separates the caudate nucleus and thalamus medi ally from the lentiform nucleus laterally. ■ consists of three divisions:

Copyright © 2023 Wolters Kluwer, Inc. Unauthorized reproduction of the content is prohibited. A. Anterior limb ■ located between the caudate nucleus and the lentiform nucleus.

B. Genu

■ contains corticobulbar fibers.