Faculty of Dental Medicine and Surgery

Sem 4

Cerebellum

Dr. Muzamil

Cerebellar physiology

Dr. Muzamil Ahmed

structural division of Cerebellum

Anterior Lobe

Posterior Lobe

Flocculo-NodularLobe (FN lobe)

Primary fissure

functional division of cerebellum

Functions of cerebellum

Maintenance of equilibrium (balance) by Vestibulocerebellum.

This lobe & dentate nuclei receive direct afferents from vestibular apparatus (Equilibrium receptors) & indirect afferents from brain stem vestibular nuclei.

The efferent from this lobe to the brain stem help in equilibrium.

Planning & programming of movements by Cerebrocerebellum with Basal ganglia & motor cortex.

Coordination of movements by Spinocerebellum.

Coordination: Execution of movements according to desired rate, range, force & direction.

Facilitatory & inhibitory to gamma motor neuron & muscle tone, with dominant Facilitation.

Cerebellar lesion

• Signs & symptoms occur in the muscles of the same side of the lesion. Include:

1. Hypotonia.

2. Ataxia: Incoordination of movement due to errors in the rate, range, force & direction of the movement.

3. Loss of balance... Vertigo, Nystagmus…

Manifestations of ataxia

• Staggering (drunken) gait: Wide based unsteady gait.

• Slurred, (dysarthric,drunken) speech• Dysmetria (past pointing)• Kinetic (intention) tremors.• Dysdiadochokinesia: Inability to perform

rapid.repeated alternating movements (pronation & supination of the hands).

• Rebound phenomenon.

Tests of cerebellar lesion

• The End