Deep Cerebellar Nuclei and Connections of Functional Divisions

00:00 Associated with the cerebellum would be a population of cerebellar nuclei. These cerebellar nuclei have efferent or outputs. So we’ll explore the nuclei and what their output is. Where are they going? What are they signaling? What is that circuit between them and another structure? The first nucleus to point out is the fastigial nucleus. It’s identified in this region and we see it here on the opposite side.

00:39 Output from the fastigial nucleus will be to the vestibular nucleus, that nucleus that will help control equilibrium or balance. We also have a collection of nuclei that I’m going to just call the interposed nucleus. There are three of them identified here, here, and here. These are shown, at least two of them are shown over here on the opposite side. Then the third one that is not present in this oblique section would reside along here. The interposed nucleus connects to the red nucleus in the midbrain. It also has connections to the reticular formation in the brain stem. The most prominent nucleus is the dentate nucleus.

01:35 You can see the irregular contour of this very large nucleus and here it is on the opposite side.

01:44 This projects to the thalamus specifically the ventral anterior and ventral lateral thalamic nuclei.

01:57 The fastigial nucleus projects efferents via the inferior cerebellar peduncle to the medullary and pontine regions of the brainstem, including the vestibular nucleus and reticular formation for the control of equilibrium, as part of the fastigioreticular tract. The interposed nuclei sends efferents via the superior cerebellar peduncle to the thalamus, cerebral cortex, basal ganglia, the red nucleus and the reticular formation to coordinate the reciprocal contraction of agonist and antagonist muscles.

02:26 The dentate nucleus also sends afferents to the thalamus and cerebral cortex to coordinate sequential movements initiated in the cortex.

02:34 The cerebellum can also be defined functionally. This functional definition is going to be by connections from these functional divisions. First is the vestibulocerebellum. The vestibulocerebellum would connect between the cerebellum and the vestibular nucleus. The vestibulocerebellum is the flocculonodular lobe that we see here. The spinocerebellum is the connection between the cerebellum and the pathways in the spinal cord. This is occurring within the intermediate hemisphere. So the intermediate hemisphere represents the spinocerebellum. Then lastly, we have a connection between the cerebellum and the pons.

03:35 This constitutes the pontocerebellum. This functional division is represented by the lateral hemisphere.