Chapter 13 Diencephalon: Thalamus and Hypothalamus


■ when destroyed, results in memory loss (Wernicke–Korsakoff syndrome). ■ plays a role in the expression of affect, emotion, and behavior (limbic function).

C. Intralaminar nuclei ■ receive input from the brainstem reticular formation, the ascending reticular activating system, and other thalamic nuclei. ■ receive spinothalamic and trigeminothalamic input via the spinal lemniscus.

■ project diffusely to the neocortex. ■ project to the dorsomedial nucleus. 1. Centromedian nucleus

■ largest of the intralaminar nuclei. ■ reciprocally connected to the motor cortex (area 4). ■ receives input from the globus pallidus. ■ projects to the striatum.

■ projects diffusely to the neocortex. ■ plays a role in attention and arousal. 2. Parafascicular nucleus ■ projects to the striatum and the supplementary motor cortex (area 6). ■ plays a role in changing patterns of response to stimuli.

D. Dorsal tier nuclei

1. Lateral dorsal nucleus ■ a posterior extension of the anterior nuclear complex. ■ receives mammillothalamic input. ■ projects to the cingulate gyrus. ■ has reciprocal connections with the limbic system. ■ plays a role in spatial learning and memory. 2. Lateral posterior nucleus ■ located between the lateral dorsal nucleus and the pulvinar. ■ has reciprocal connections with the superior parietal cortex (areas 5 and 7). ■ plays a role in visual and spatial attention. ■ often considered with the pulvinar as part of the pulvinar-LP complex. 3. Pulvinar ■ the largest thalamic nucleus (actually a series of interconnected subnuclei). ■ has reciprocal connections with the association cortex of the occipital, parietal, and pos terior temporal lobes. ■ receives input from the lateral and medial geniculate bodies (MGBs) and the superior colliculus. ■ concerned with visual attention and appropriate motor activities in coordination with oculomotor function. ■ lesions of the dominant side may result in sensory aphasia. ■ receives input from the globus pallidus and the substantia nigra. ■ projects diffusely to the prefrontal and orbital cortices. ■ projects to the premotor cortex (area 6). ■ functions in conjunction with the basal nuclei. 2. Ventral lateral nucleus ■ receives input from the globus pallidus, substantia nigra, and the cerebellum (dentate nucleus). ■ projects to the motor cortex (area 4) and to the supplementary motor area (area 6). ■ influences somatic motor mechanisms via the striatal motor system and the cerebellum. ■ destruction reduces Parkinsonian tremor. 3. Ventral posterior nucleus ■ the nucleus of termination of general somatic afferent (pain and temperature) and spe cial visceral afferent (SVA; taste) pathways.

E. Ventral tier nuclei ■ include primarily specific relay nuclei: 1. Ventral anterior nucleus

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