Cerebellum Flashcards
Vermis and Paravermian portions of cerebellum
control axial musculature (neck and trunk muscles)
Lateral hemispheres of cerebellum
control limb musculature
Flocculonodular lobe
- maintains balance
- coordinates head and eye movements with vestibular system
Deep cerebellar nuclei
relay point for efferents from cerebellum to other brain regions; include Dentate, Interpositus (Globose + Emboliform), Fastigial nuclei
Dentate nucleus
- receives input from lateral cerebellar hemispheres
- projects to thalamus
Interpositus nucleui
(= Globose and Emboliform)
- receive inputs from paravermal zones
- projects to red nucleus
Fastigial nucleus
- receives input from vermis
- projects to vestibular nuclei and reticular formation (bilaterally)
Superior Cerebellar peduncle
- afferents: anterior/ventral SCT, acoustic and optic information
- efferents: (to forebrain) dentato-rubro-thalamic (to Red nucleus) and dentato-thalamic (to thalamus) tracts
Middle Cerebellar peduncle
- afferents: pontocerebellar tract (from contralateral cortex)
- efferents: none
Inferior Cerebellar peduncle
- afferents: vestibulo-cerebellar, olivo-cerebellar, posterior spinocerebellar tracts
- efferents: cerebellovestibular and cerebelloolivary tracts
Layers of Cerebellar cortex
- Molecular - outermost, basket and stellate cells
- Purkinje cell layer - purkinje cell bodies
- Granular layer - granule and golgi cells
- White matter - tracts/projections
Input to cerebellum from outside cerebellum
- Climbing fibers (excitatory) –> Purkinje cells
2. Mossy fibers (excitatory) –> Granule and Golgi cells (in cerebellar glomeruli)
Modulators of Purkinje cells
- Granule cells (excitatory; pass along modified information they get from mossy fibers)
- Basket/Stellate cells have inhibitory effect on Purkinjes
Vestibulocerebellum
- afferents from ispi vestibular nuclei in brainstem via inferior peduncle to FN lobe and inferior paravermal area
- efferents to fastigial nucleus which then projects to bilateral vestibular nuclei and reticular formation
- functions to coordinate eye, head, neck movements, and maintain body balance
Spinocerebellum
- receives the dorsal SCT via inferior peduncle
- also, spinal border cells send copy of LMN’s via ventral SCT (via superior peduncle)
- inferior olive provides information on the contralateral limb
- truncal movements processed in vermis, output via fastigial nucleus to rubrospinal, vestibulospinal, reticulospinal tracts
- limb movements processed in anterior lobe (L lobe = L limbs), sent to EG nuclei, VL of thalamus, M1, CST
Cerebrocerebellum
- comprises lateral posterior lobes
- input from pontine nuclei (via MCP)
- output via dentate to red nucleus to VL thalamus (also direct dentato-thalamic output), then to M1
- needed for hand-eye coordination to reach/manipulate an object, as well as automaticity of aspects of cognition as well as fluidity of language
Clinical signs of cerebellar dysfunction
- unstable gait, wide stance
- jerky movements, intention tremor
- ataxia of trunk/limbs
- dysmetria of movements
- eye movement disorders, i.e., nystagmus, saccadic/smooth pursuit dysmetria
- speech disorders, i.e., ataxia dysarthria, difficulty with rhythm and intonation
