30. Cerebellum 2025

What is the primary role of the cerebellum?

To monitor and correct ongoing movements

What is the result of cerebellar correction?

Movements are accurate and smoothly executed

What does the cerebellum control along with the basal ganglia?

Activity of the motor and premotor cortices

What fuses the two hemispheres of the cerebellum?

The vermis

What are the three lobes of each cerebellar hemisphere?

Anterior, posterior, and flocculonodular lobes

Which is the largest lobe of the cerebellum?

The posterior lobe

What is the folded surface of the cerebellar cortex called?

Folia

What are the four deep cerebellar nuclei from medial to lateral?

Fastigial, Globose, Emboliform, Dentate

What are the two major cerebellar input fibers?

Climbing fibers and mossy fibers

What is the main output cell of the cerebellar cortex?

Purkinje cell

What does the superior cerebellar peduncle connect to?

Midbrain

What is the primary function of the superior cerebellar peduncle?

Main output of the cerebellum

What does the middle cerebellar peduncle connect to?

Pons

What is the function of the middle cerebellar peduncle?

Main input from the cortex to the cerebellum

What does the inferior cerebellar peduncle connect to?

Medulla

What is the function of the inferior cerebellar peduncle?

Main input from the spinal cord to the cerebellum

What is the vestibulocerebellum responsible for?

Maintaining balance via the vestibular system

What is the spinocerebellum responsible for?

Maintaining posture and balance of limbs/trunk via proprioception

What is the cerebrocerebellum responsible for?

Planning voluntary movement via cortical input

Where does the cerebrocerebellar pathway begin?

Contralateral motor cortex

What brainstem nucleus is involved in the pathway?

Contralateral pontine nucleus

Which peduncle carries this input to the cerebellum?

Middle cerebellar peduncle

Which cerebellar cells receive the input?

Ipsilateral Purkinje cells

Which deep cerebellar nucleus is involved?

Ipsilateral dentate nucleus

Which peduncle carries cerebellar output back to the cortex?

Superior cerebellar peduncle

What thalamic nucleus relays to cortex?

Contralateral ventrolateral (VL) thalamus

Where does the signal return in the cortex?

Contralateral motor cortex

How does the signal return to the body?

Corticospinal tract via internal capsule → cerebral peduncle → medulla (decussates) → spinal cord → anterior horn

How many times does the cerebrocerebellar pathway decussate?

Twice

Why do cerebellar lesions produce ipsilateral symptoms?

Because of double decussation in input and output pathways

What is disequilibrium?

Imbalance, dizziness, and vertigo

What is nystagmus in cerebellar disease?

Multidirectional rapid alternating eye movements

What distinguishes vestibular nystagmus?

Usually unidirectional

What is ataxia?

Impaired motor coordination

What is dysmetria?

Impaired fine motor coordination

What causes cerebellar tremor?

Inability to balance flexor and extensor muscle tone