Cerebellum Modular Organization
CEREBELLAR CORTICONUCLEAR PROJECTION Output from the cerebellar cortex to the DCN is derived exclusively from PCs and is inhibitory. The vermis projects to the fastigial nucleus, the intermediate cortex project…
Cerebrocerebellar Connections
In the cerebral peduncle, prefrontal fibers are most medial, sensorimotor fibers intermediate, and fibers from the parietal, temporal, and occipital lobes are lateral. In the monkey, terminations in the pons…
Cerebellar Motor Examination
Eye Movements. Cerebellar lesions produce unsteady ocular fixation in primary position, microsaccadic oscillations, square wave jerks, ocular flutter, ocular bobbing, and opsoclonus. Pursuit eye movements show saccadic intrusions—jerkiness following a…
Cerebellar Efferent Pathways
The exception to the PC-DCN projection pattern throughout the cerebellum is the vestibulocerebellar cortex (vermal part of lobule IX [uvula], vermal [nodulus], and hemispheric parts [flocculus] of lobule X), which…
Cerebellovestibular Pathways
VESTIBULOCEREBELLAR PROJECTIONS There are five peripheral vestibular end organs; the cristae in the three orthogonally oriented semicircular canals detect movement in the sense of angular rotation in the horizontal, pitch,…
Cerebellum Subdivisions and Afferent Pathways
Knowledge of cerebellar connections with extracerebellar structures is critical to understanding the diverse roles of the cerebellum and the consequences of cerebellar injury. Afferents to cerebellum are conveyed predominantly by…
Cerebellum Subdivisions and Afferent Pathways (Continued)
Trigeminocerebellar projections from the principal trigeminal sensory nucleus travel in the ICP to the face representation in caudal lobule V and lobule VI; in contrast, cerebellar projections from the mesencephalic…
Cerebellar Cortical and Corticonuclear Circuitry
Climbing fibers (CFs) arise exclusively from the inferior olive. Axons of olivary neurons branch to form 7 to 10 CFs. Each CF provides extensive excitatory synaptic contact with the dendritic…
Cerebellar Cortical and Corticonuclear Circuitry (Continued)
The two major neurotransmitters in the cerebellum are glutamate and γ-aminobutyric acid (GABA). Glutamate is excitatory and is found in the MFs, PFs, CFs, UBCs, and deep cerebellar nuclear neurons…
Cerebellar Cortex and Nuclei (Continued)
The unipolar brush cell (UBC) is the only excitatory interneuron in the cerebellum. The soma is 9 to 12 µm in diameter, with a single dendrite ending in a tight…
