AN60.1-3 | Cerebellum — Glossary

Structure in the posterior fossa that coordinates movement, maintains posture, and regulates muscle tone; does not initiate movements but modulates them

Midline strip of the cerebellum connecting the two hemispheres; part of the spinocerebellum controlling trunk posture and gait

Transversely oriented surface ridges of the cerebellum equivalent to cerebral gyri

Largest and most lateral intracerebellar nucleus; output for voluntary fine movements via the superior cerebellar peduncle to the VL thalamus

Most medial intracerebellar nucleus; output for balance and posture via cerebellovestibular fibres

Large flask-shaped neuron in the cerebellar cortex; the ONLY output of the cortex; GABAergic (inhibitory) projection to deep nuclei

Most numerous neuron in the entire CNS; excitatory (glutamate); located in the deepest cerebellar cortical layer; sends parallel fibres to the molecular layer

Tree of life — branching pattern of white matter seen on midsagittal section of the cerebellum

Inability to accurately reach a target (past-pointing or undershooting) on the finger-nose test; sign of cerebellar hemisphere lesion

Tremor that worsens as the limb approaches a target; characteristic of cerebellar disease; contrasts with resting tremor of Parkinson's

Inability to perform rapid alternating movements (e.g., pronation/supination); sign of cerebellar hemisphere dysfunction

Staccato, explosive, measured speech with irregular emphasis; sign of cerebellar dysfunction

Involuntary rhythmic eye movements; cerebellar nystagmus is typically gaze-evoked and maximal looking toward the side of the lesion

Test for sensory ataxia: patient stands with feet together and eyes closed; positive (falls) in posterior column disease, negative in cerebellar disease

Most common malignant brain tumour in children; arises in the cerebellar vermis; causes hydrocephalus by blocking the 4th ventricle

Incoordination of voluntary movement; cerebellar ataxia is ipsilateral and not worsened by eye closure (unlike sensory ataxia)

Main output pathway of the cerebellum via the superior cerebellar peduncle; crosses in the midbrain to reach the contralateral red nucleus and VL thalamus

Climbing fibres from the inferior olivary nucleus to the cerebellar cortex; carry error signals for motor learning

Posterior (Clarke's column) and anterior tracts carrying unconscious proprioception from the body to the cerebellum

Cerebellar tonsillar herniation through the foramen magnum; Type I causes syringomyelia, Type II is associated with myelomeningocele

Decreased muscle tone; in cerebellar disease, causes pendular reflexes (knee jerk swings back and forth instead of a single response)

Knee jerk response that swings back and forth like a pendulum instead of a single contraction; sign of cerebellar hypotonia