Intracerebellar deep cerebellar nuclei

The brainstem is presented from the anterior perspective, with the cerebellum attached (as in Figure 6, Figure 7, Figure 8A, and Figure 8B). This diagram shows the intracerebellar nuclei — also called the deep cerebellar nuclei — within the cerebellum.

There are four pairs of deep cerebellar nuclei — the fastigial nucleus, the globose and emboliform nuclei (together called the intermediate or interposed nucleus), and the lateral or dentate nucleus. Each belongs to a different functional part of the cerebellum. These nuclei are the output nuclei of the cerebellum to other parts of the central nervous system.

• The fastigial (medial) nucleus is located next to the midline.

• The globose and emboliform nuclei are slightly more lateral; often these are grouped together and called the intermediate or interposed nucleus.

• The dentate nucleus, with its irregular margin, is most lateral. This nucleus is sometimes called the lateral nucleus and is by far the largest.

The nuclei are located within the cerebellum at the level of the junction of the medulla and the pons. Therefore, the cross-sections shown at this level (see Figure 66C) may include these deep cerebellar nuclei. Usually, only the dentate nucleus can be identified in sections of the gross brainstem and cerebellum done at this level (see Figure 67).

Two of the afferent fiber systems are shown on the left side — representing cortico-ponto-cerebellar fibers and spino-cerebellar fibers. All afferent fibers send collaterals to the deep cerebellar nuclei en route to the cerebellar cortex, and these are excitatory. Therefore, these neurons are maintained in a chronic state of activity.

The lateral vestibular nucleus functions as an additional deep cerebellar nucleus, because its main input is from the vestibulocerebellum (shown in the next illustration); its output is to the spinal cord (see Figure 50).

Cerebellar Nuclei

FIGURE 56A: Cerebellum 3 — Intracerebellar (Deep Cerebellar) Nuclei

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