Cerebellar Control of Movement

Question 1

What percentage of brain volume does the cerebellum take?

Answer 1

10%

Question 2

What percentage of brain neurons does the cerebellum take?

Answer 2

50%

Question 3

T/F: cerebellum directly controls posture and regulation of movement

Answer 3

False. Regulation of movements and INDIRECT control of posture

Question 4

T/F: cerebellum not essential for muscle contraction

Answer 4

True.

Question 5

What happens when cerebellum is damaged?

Answer 5

loss of motor coordination

Question 6

Purpose of convoluted structure of cerebellum

Answer 6

to accommodate a large surface area

Question 7

Paleocerebellum

Answer 7

anterior lobe

Question 8

Neocerebellum

Answer 8

Posterior lobe

Question 9

Archicerebellum

Answer 9

Flocculonodular lobe

Question 10

What separates anterior and posterior lobes?

Answer 10

Primary fissure

Question 11

What separates superior and inferior semilunar lobules?

Answer 11

Horizontal fissure

Question 12

What separates posterior and flocculonodular lobes?

Answer 12

paraflocculus and posterolateral fissure

Question 13

Two longitudinal grooves

Answer 13

vermis (medial)

hemispheres: intermediate, lateral

Question 14

somatotopy

Answer 14

when a specific part of the body is associated with a distinct location in the CNS

Question 15

Cellular organization of cerebellar cortex (5 and 3)

Answer 15

5 different types of neurons and 3 distinct cell layers

Question 16

cerebellar cortex input: output ratio

Answer 16

40:1

Question 17

T/F: integration of large amounts of information happens in cerebellar cortex

Answer 17

True

Question 18

Three cell layers of CB cortex

Answer 18

Molecular layer
purkinje layer
granular layer

Question 19

five neuron types of CB cortex

Answer 19

Basket cell
Stellate cell
Purkinje cell
Granule cell
Golgi cell

Question 20

Inputs to cerebellum

Answer 20

Mossy fibers

Climbing fibers

Question 21

What sends info from brainstem and spinal cord via (probably) spinocerebellar tract?

Answer 21

Mossy fibers

Question 22

What sends info from medulla (inferior olive)?

Answer 22

climbing fibers

Question 23

What influences purkinje cell indirectly via interneurons (granule cells +) (need summation for APs in P cell)?

Answer 23

Mossy fibers

Question 24

What directly synapses on purkinje cell?

Answer 24

Climbing fibers

Question 25

What has very powerful synapse -- 1 AP in this fiber = large EPSP = AP?

Answer 25

Climbing fibers

Question 26

Functional divisions of the cerebellum

Answer 26

vestibulocerebellum spinocerebellum cerebrocerebellum

Question 27

functional subdivisions of the spinocerebellar and cerebrocerebellar regions

Answer 27

vermis intermediate hemisphere lateral hemisphere

Question 28

motor execution

Answer 28

vermis -> fastigial nucleus -> to medial descending systems | intermediate hemisphere -> interposed nucleus -> to lateral descending systems

Question 29

motor planning

Answer 29

cerebrocerebellum -> dentate nucleus -> to motor and premotor cortices

Question 30

balance and eye movements

Answer 30

vestibulocerebellum -> to vestibular nuclei

Question 31

location receiving corticopontine inputs

Answer 31

cerebrocerebellum (lateral hemisphere) | vestibulocerebellum

Question 32

location receiving spinal and trigeminal inputs

Answer 32

spinocerebellum (vermis and intermediate hemisphere)

Question 33

what does efferent signals go from fastigial nucleus?

Answer 33

1. brainstem -> spinal cord | 2. cerebral cortex -> spinal cord

Question 34

what does vermis control

Answer 34

axial and proximal muscles involved in posture (balance), gait

Question 35

intermediate hemispheres pathway

Answer 35

interpositus nucleus -> brainstem/cerebral cortex -> spinal cord

Question 36

what is the comparator function of the cerebellum

Answer 36

update and correct for errors in ongoing movement using efferent copy of motor output to cb - compare actual with desired movement

Question 37

pathway going to cerebrocerebellum

Answer 37

cerebral cortex -> brain stem -> cerebrocerebellum

Question 38

pathway exiting cerebrocerebellum

Answer 38

dentate nucleus -> thalamus -> cerebral cortex

Question 39

role of cerebrocerebellum in movement

Answer 39

initiation planning timing (setting up of "motor commands" responsible for coordinated movement)

Question 40

what will happen if dentate is destroyed (lesions)?

Answer 40

delayed movement onset dysmetria disorders in spatial coordination of hand and finger muscles

Question 41

why the results of dentate lesions? (delayed movement onset dysmetria disorders in spatial coordination of hand and finger muscles)

Answer 41

all due to improperly timed muscle activity

Question 42

What do pts with cb lesions lack in the Prism adaptation studies?

Answer 42

motor adaptation

Question 43

T/F: contralateral symptoms are produced in cerebellar dysfunction

Answer 43

False. Cerebellar dysfunction produces ipsilateral symptoms

Question 44

Clinical symptoms of cerebellar dysfunction (7)

Answer 44

1. Balance disorders 2. ataxia (dysmetria, dysdiadochokinesia, decomposition of movement) 3. hypotonia 4. intention tremor 5. gait problems 6. eye movement disorders 7. dysarthria

Question 45

what does ataxia have problems in

Answer 45

rate, range, and direction of movement

Question 46

potential reason of overshooting in hypermetria

Answer 46

poor timing of antagonist muscle

Question 47

what is muscle tone like in hypotonia, why?

Answer 47

low muscle tone possibly due to a decrease in gamma drive

Question 48

what is muscle tone

Answer 48

passive resistance to muscle stretch, role of gamma system

Question 49

T/F: muscle tone involves stretch reflex

Answer 49

True

Question 50

what is intention tremor

Answer 50

involuntary oscillations seen during movement | may be superimposed on dysmetric movements

Question 51

dysarthria

Answer 51

speech impairment

Question 52

CB dysfunction vs Parkinson's

Answer 52

CB: -vvvvv- | Parkinson's: vvv-------vvv