Cerebellum

Question 1

Define the major anatomical subdivisions of the cerebellar cortex and deep cerebellar nuclei.

Answer 1

Cerebellar cortex
* pontocerebellum
* spinocerebellum
* vestibulocerebellum

Deep cerebellar nuclei
* dentate nucleus
* interposed nuclei
* fastigial nucleus

Question 2

What are the 3 lobes of the cerebellar cortex

Answer 2

1. flocculonodular
2. anterior
3. posterior

Question 3

Answer 3

Question 4

What are the 3 cerebellar cortial layers & the cell types found there?

Answer 4

1. molecular layer - purkinje dendrites, granule cell axons, inferior olivary climbing fibres
2. Purkinje cell layer - purkinje cell bodies
3. granule cell layer - granule cell bodies

Question 5

What type of cell is this?

Answer 5

purkinje cell

Question 6

Describe the major efferent and afferent circuitry of the cerebellar cortex including the local circuitry.

Answer 6

Afferents:
* to the granule cells (from mossy fibers, originating all over CNS
* to the purkinje cells (from climbing fibres, originating in inferior olicary nucleus)

Efferents:
* Purkinje cells are the main output neurons & provide inhibitory control over deep cerebellar nuclei.

Internal Circuitry:
* direct loop from climbing fibred & granule cells to purkinje cells (all excitatory) to purkinje output
* parallel fibres in molecular layer formed by granule cells also excitatory synapse onto basket cells and golgi cells
* basket cells inhibit purkinje cells
* golgi cells inhibit basket cells (and also receive inhibitory input from purkinje cells)

Question 7

Identify the three major cerebellar peduncles and define their afferent and efferent pathways.

Answer 7

Superior
* afferent from spinal cord & colliculi
* efferent to superior colliculi, areaas 4&6 via ventral lateral thalamus

Middle - biggest pathway in the brain
* afferent from pontine nuclei
* no efferent

Inferior
* afferent from inferior olivary complex, spinal cord & vestibular nerve
* efferent to vestibular nuclei, retiular formation, red nucleus

Question 8

identify the functional areas of the cerebellum

Answer 8

Question 9

What are the function, afferent and efferent pathways of the 3 major functional subdivisions of the cerebellum

Answer 9

Vestibulocerebellum
* maintenance of balance, coordination of head/eye movements
* input from vestibular nuclei & vestibular organs
* output directly back to them via fatigial nucleus

Spinocerebellum
* control of posture & movements under continuous sensory control
* input from spinal cord, visual, auditory and vestibular systems, motor and premotor cortex
* output via fastigial and interposed nuclei to reticular formation, vestibular nuclei, cranial motor nuclei, red nucleus, thalamus -cortex

Pontocerebellum
* fine motor control,
* input from neocortex (all motor and somatosensory areas, some visual/limbic) via pontine nuclei (this is why its aka cerebocerebellum)
* output via dentate nucleus to motor/premotor cortex via ventral lateral thalamus & to red nucleus