Cerebellum

Question 1

What is the cerebellum responsible for?

Answer 1

-Motor area of the brain maintaining equilibrium and muscle contractions
-Ensures that the contraction of the correct muscle occurs at the right time with correct force
-Plays a role in learning patterns of neuronal activity for carrying out movement
-may have sensory and cognitive functions

Question 2

Describe the connections of the cerebellum

Answer 2

-Cerebellum receives input from regions of cerebral cortex that plan and initiate skilled movements
- Also receives information from sensory systems that monitor course of movements
-Computes a “motor error” from these inputs
-Corrects output of motor cortex via its thalamic connections – does not project to LMN in BS or SC
-Corrections occur in real time, but also over longer periods, as in motor learning
-Major afferent and efferent pathways form a loop between the cerebral cortex, brainstem and spinal cord

Question 3

What is the 2 major anatomical divisions of the cerebellum?

Answer 3

-cerebellar cortex
-deep cerebellar nuclei

Question 4

What are the constitutes of the cerebellar cortex?

Answer 4

-Pontocerebellum
-Spinocerebellum
-Vestibulocerebellum

Question 5

What constitutes the deep cerebellar nuclei

Answer 5

-Dentate nucleus
-Interposed nuclei
-Fastigial nucleus

Question 6

what are the lobes of the cerebellum?

Answer 6

-flocculonodular
-anterior
-posterior

Question 7

What are the layers of the cerebellar cortex?

Answer 7

3 cortical layers:
-molecular
-Purkinje cell
-granule cell

Question 8

Describe the granule cell glomeruli

Answer 8

-mossy fibres synapse with neurons in the granule layer to form glomeruli

Question 9

what are the major tracts of the cerebellum?

Answer 9

-3 major tracts (peduncles):
–superior
–middle
–inferior

Question 10

describe the superior peduncle of cerebellum

Answer 10

-afferent input from sc, colliculi

-efferent output to the UMN in sup.
colliculus and M1 (area 4) & PMA
(area 6), via ventral lateral thalamus

Question 11

describe the middle peduncle of the cerebellum

Answer 11

-afferent input from the pontine nuclei

Question 12

Describe the inferior peduncle of the cerebellum

Answer 12

-afferent input from inferior olive, sc, vestibular nerve

-efferent to the vestibular nuclei and reticular formation

Question 13

what is the structural anatomy of the cerebellum

Answer 13

-flocculonodular lobe
-vermis, paravermis
-lateral hemispheres

Question 14

what is the phylogenetic anatomy of the cerebellum

Answer 14

-archicerebellum
-paleocerebellum
-neocerebellum

Question 15

what is the function anatomy of the cerebellum?

Answer 15

-vestibulocerebellum
-spinocerebellum
-pontocerebellum

Question 16

Describe the Vestibulocerebellum

Answer 16

-Occupies the flocculonodular lobe (flocculus and nodule of vermis)
-Input from vestibular nuclei, vestibular organs (position and movement of the head)
-Output directly back to them via the fastigial nucleus
-Influences motor activity via the vestibulospinal tract, reticulospinal tract and the medial longitudinal fasciculus
-Functions in maintenance of balance, co-ordination of head & eye movements

Question 17

describe the spinocerebellum

Answer 17

-Paravermis and vermis (except the nodule)

-Input spinal cord (esp. dorsal & ventral spinocerebellar tracts, cuneocerebellar tracts and trigeminal nucleus), visual, auditory and vestibular systems, motor and premotor cortices

-Outputs via the interposed and fastigial nuclei to reticular formation, vestibular nuclei, motor nuclei of cranial nerves, red nucleus, via thalamus to cortex

-Regulation of posture & movements under continuous sensory control

Question 18

describe the pontocerebellum

Answer 18

-Lateral cerebellar hemispheres.

-Input from neocortex, from all motor and somatosensory areas and association cortex via the pontine nuclei, some from visual cortex and limbic system

-output is through the dentate nucleus, to motor and premotor cortex via the thalamus (VL), the red nucleus of the midbrain

-Influences corticospinal, corticoreticular and reticulospinal pathways

-Initiation, execution of preprogrammed rapid movements, co-ordination of fine movement

Question 19

What is cerebellar ataxia

Answer 19

-damage to the cerebellum produces jerky, imprecise movements
-ipsilateral nature of symptoms
-somatotopy results in regional specificity of symptoms

Question 20

What is nystagmus?

Answer 20

-vestibulocerebellum damage
-inability to stand upright

Question 21

what is dysmetria?

Answer 21

-dysmetria
-abnormal gait
-action tremors

Question 22

what happens with pontocerebellum damage?

Answer 22

impairments in highly skilled movements