NETTER - Neuroscience Flash Cards

Cerebellar Organization:
Lobes and Regions
1. Lateral hemisphere
2. Paravermis
3. Vermis
4. Anterior lobe
5. Primary fissure
6. Posterior lobe
7. Flocculonodular lobe
8. Nodule
9. Flocculus
Comment: The cerebellum is subdivided by lobes (anterior,
posterior, flocculonodular) and longitudinal organization (vermis,
paravermis, lateral hemispheres). Damage to the flocculonodular
lobe produces truncal ataxia and a broad-based uncoordinated
gait. Damage confined to the anterior lobe results in a staggering
gait with stiff-legged movement, brought about by disinhibition of
anterior lobe connections with the lateral vestibulospinal system.
Posterior lobe damage (affecting lateral hemispheres) produces
additional problems beyond truncal ataxia, including limb ataxia,
dysmetria, dysdiadochokinesia (inability to perform rapid alternating
movements), intention tremor, and hypotonia. The longitudinal
organization reflects connectivity of the hemispheres with the deep
cerebellar nuclei and their influence over upper motor neuronal
groups. The vermis and flocculonodular lobe connect with the
fastigial nucleus and lateral vestibular nucleus, which regulate
vestibulospinal and reticulospinal tract activity (ipsilateral). The
paravermis connects with globose and emboliform nuclei, which
regulate mainly rubrospinal tract activity. The lateral cerebellar
hemispheres connect with the dentate nucleus, which regulates
mainly corticospinal tract activity via the ventral lateral nucleus of
the thalamus. These two connections from the deep nuclei to their
upper motor neurons (UMNs) are crossed, and UMN projections are
crossed. Cerebellar influences over motor activity are ipsilateral, as
are the symptoms that occur with damage.
Regional Neuroscience See book 11.34