Chapter 19- Sensorimotor functions of the cerebellum

Question 1

what part of the brain controls agonist/antagonist action ?

Answer 1

cerebellum

Question 2

what are the white matter in the cerebellum connected to ?

Answer 2

brainstem

Question 3

what in the cerebellum works as a fast highway to the brain ?

Answer 3

the cerebellar peduncles

Question 4

what are the three parts of the cerebellum ?

Answer 4

1) spinocerebellum (medial) has afferent input from spinal cord
2) cerebrocerebellum (lateral) has major afferent input from cerebrum
3) vestibulocerebellum (inferior) is responsible for balance, eye movement control

Question 5

what are the cerebellar nuclei that talk to the VA/VL complex of thalamus ?

Answer 5

deep cerebellar nuclei

Question 6

the left cerebellum controls which limb ?

Answer 6

ipsilateral limb, since the info is coming from the contralateral brain hemisphere

Question 7

the left cerebral hemisphere goes to which cerebellar hemisphere ?

Answer 7

right (contralateral) hemisphere

Question 8

what is the fastest cerebellar tract ?

Answer 8

cerebropontocerebellar

from frontal/parietal cortex to pontine nuclei (then crosses over) to cerebellar cortex/ deep nuclei

Question 9

the spinocerebellum contains two somatotopic maps of the body- what do they look like ? what is this indicative of ?

Answer 9

bonhomme a lenvers and bonhomme facing outward

cerebellum has receptive fields that are functional but not precise

Question 10

describe the way receptive fields are positioned in the cerebellum

Answer 10

they’re intermingled, that way local circuits can interact more easily

Question 11

what is the cerebellar output from the cerebrocerebellum ?

Answer 11

deep cerebellar nuclei (dentate) and then to premotor cortex for motor planning

Question 12

what is the cerebellar output from the spinocerebellum ?

Answer 12

interposed and fastigial nuclei and then to motor cortex and brainstem for motor execution and control of ongoing movements

Question 13

what is the cerebellar output from the vestibulocerebellum ?

Answer 13

vestibular nuclei, and then lower motor neurons in spinal cord and brainstem for balance and VOR

Question 14

how is cerebellar output directly connected to the cortex ?

Answer 14

it isn’t

Question 15

what are the main upper motor neurons affected by the cerebellum ?

Answer 15

superior cerebellar peduncle and onto

• VA/VL complex of thalamus and onto primary motor cortex
• superior coliculi

Question 16

deep cerebellar nuclei that are dentate/interposed will be responsible for the lower motor neurons of what parts of the body ?

Answer 16

lateral

Question 17

deep cerebellar nuclei that are fastigial will be responsible for the lower motor neurons of what parts of the body ?

Answer 17

medial/axial

Question 18

the right cerebellar hemisphere will be responsible for which superior colliculus ?

Answer 18

left (controlling saccades towards right part of visual field)

Question 19

which fibers are Purkinje cells connected to ?

Answer 19

parallel fibers and climbing fibers

Question 20

what is the strongest synapse in the nervous system ?

Answer 20

Purkinje and climbing fibers - climbing fibers “hug” Purkinje fibers

excitatory

Question 21

what are the three layers of the cerebellum ?

Answer 21

1) molecular
2) purkinje cell
3) granule cell

Question 22

where do climbing fibers come from ?

Answer 22

inferior olive

Question 23

where do parallel fibers come from ?

Answer 23

granule cells

Question 24

what happens when climbing fiber has an AP ?

Answer 24

A single action potential in a climbing fiber elicits a burst of action potentials in the Purkinje cells that it contacts.

Question 25

explain how parallel fibers are formed

Answer 25

Granule cells have long axons that pass dorsally through the granule and Purkinje, cell layers to reach the molecular layer of the cerebellar cortex, where they bifurcate and run PARALLEL to the long axis of the folium.

Question 26

how is the effect of a single parallel fiber on a Purkinje cell ?

Answer 26

weak especially compared to the climbing fibers but excitatory

Question 27

what are mossy fibers ?

Answer 27

axons of inputs into cerebellum

Each swelling, called a “rosette”, is a synapse of the mossy fiber onto the dendrite of a granule cell.

Question 28

The output of the Purkinje

cell onto the deep cerebellar nuclear cell is inhibitory or excitatory ?

Answer 28

inhibitory

Question 29

which cells in the cerebellar cortex are output cells ?

Answer 29

Purkinje

Question 30

what is low volume but very strong input cells ?

Answer 30

climbing fibers

Question 31

what are large-body, all encompassing fiber ?

Answer 31

mossy fibers

Question 32

what are the two loops in the cerebellar circuit ?

Answer 32

main excitatory and side cortical inhibition loop