Sievert: Cerebellum

Question 1

What is the primary function of the cerebellum?

Answer 1

to detect differences in “motor error” - the error between the intended movement and the actual movement

Question 2

What happens to neuronal activity in the cerebellum during the course of movement?

Answer 2

it is constantly changing - the neural processing is dynamic

Question 3

In general, what do patients with cerebellar damage have problems with?

Answer 3

range, rate, and direction of movement

Question 4

What are four problems that can arise as a result of damage to the cerebellum?

Answer 4

cerebellar ataxia
dysmetria (can’t follow finger w eyes)
dysdiadochokinesia (hand flap)
**tremor when asked to perform a particular motion

Question 5

What is unique about the tremor associated with cerebellar damage?

Answer 5

when you ask a patient to perform a particular movement (i.e. touch their nose), the tremor gets worse as they approach the end point

Question 6

What are the three cerebellar peduncles?

Answer 6

superior
middle
inferior

Question 7

What are the three deep cerebellar nuclei?

Answer 7

fastigial nucleus
interposed nucleus
dentate nucleus

Question 8

In a ventral view of the cerebellum, 3 cerebellar peduncles can be seen, as well as which lobe of the cerebellum?

Answer 8

vestibulocerebellum *floculo-nodular lobe

Question 9

The midline of the cerebellum and the paramedian areas comprise which lobe?

Answer 9

spinocerebellum

Question 10

The lateral lobes of the cerebellum comprise which lobe?

Answer 10

cerebrocerebellum

Question 11

receives input from the spinal cord related to spindle information and the cortex related to execution of movements for fine control of proximal and distal muscles

Answer 11

spinocerebellum

Question 12

receives input from the premotor cortex and sensory association areas related to the planning of movements

Answer 12

cerebrocerebellum

Question 13

receives input from the vestibular system and the visual system to control eye movements and balance

Answer 13

vestibulocerebellum

Question 14

What nuclei does the spinocerebellum project to?

Answer 14

fastigial and interposed nuclei

Question 15

What nuclei does the cerebrocerebellum project to?

Answer 15

dentate nucleus

Question 16

What nucleus does the vestibulocerebellum project to?

Answer 16

vestibular nuclei
*vestibulocerebellum has no nuclei to project to within the cerebellum, so it leaves and travels to the vestibular nuclei

Question 17

Each cerebellar hemisphere has control over the (blank) side of the body. So, any inputs to the cerebellum from the cortex must (blank) and inputs from the spinal cord or vestibular nuclei must remain (blank). Similarly, outputs from the cerebellum to the cortex must also (blank) back on their way up to cortex

Answer 17

same; cross; ipsilateral; cross

Question 18

mostly efferent pathway arises from cell bodies in deep cerebellar nuclei and crosses in the midbrain on the way to the thalamus. The correction.

Answer 18

superior cerebellar peduncle

Question 19

The superior cerebellar peduncle is mostly what? Where does it arise from? Where does it cross on its way to the thalamus? What is its role?

Answer 19

mostly efferent;
arises from cell bodies in the deep cerebellar nuclei;
crosses in the midbrain;
the correction

Question 20

afferent pathway arises from cell bodies in the contralateral pontine gray which got their input primarily from the ipsilateral cerebral cortex. What the muscle are supposed to do.

Answer 20

middle cerebellar peduncle

Question 21

The middle cerebellar peduncle is a (blank) pathway. What does it arise from? What is its role?

Answer 21

afferent; arises from cell bodies in the contralateral pontine gray which got their input primarily from the ipsilateral cerebral cortex; what the muscles are supposed to do

Question 22

Mostly afferent pathway whose fibers come from cells in the spinal cord, inferior olive, vestibular nuclei and ganglion. Efferents of this peduncle project to the vestibular nuclei. What the muscles are doing.

Answer 22

inferior cerebellar peduncle

Question 23

The inferior cerebellar peduncle is mostly an (blank) pathway. Where do its fibers come from? Where do efferents of this peduncle project to? What is its role?

Answer 23

afferent; fibers come from cells in the spinal cord, inferior olive, vestibular nuclei and ganglion; efferents project to the vestibular nuclei; what the muscles are doing

Question 24

What is projecting into the cerebellum?
What is projecting out?
What is receiving from the deep nuclei?
What is the dominant source of inputs to the pontine nuclei?

Answer 24

brainstem and spinal cord structures; deep nuclei; VA/VL complex of thalamus; cortex

Question 25

What is projecting into the cerebellum?

Answer 25

brainstem and spinal cord structures

Question 26

What is projecting out of the cerebellum?

Answer 26

deep nuclei

Question 27

What is receiving input from deep nuclei?

Answer 27

VA/VL complex of thalamus

Question 28

What is the dominant source of inputs to the pontine nuclei?

Answer 28

cortex

Question 29

Where do the major inputs to the cerebrocerebellum come from?

Answer 29

``` cerebral cortex: frontal and parietal lobes motor and premotor cortex sensory cortex cingulate cortex ```

Question 30

What are the inputs to the cerebrocerebellum responsible for?

Answer 30

planning of movements

Question 31

What is the pathway from the cerebellar cortex to the primary motor cortex?

Answer 31

cerebellar cortex --> deep cerebellar nuclei --> (projections to red nucleus and superior colliculus) --> ventral lateral complex of thalamus on opposite side --> primary motor and premotor cortex

Question 32

Again, what is the pathway from cerebellar cortex to primary motor and premotor cortex?

Answer 32

cerebellar cortex --> deep cerebellar nuclei --> (superior cerebellar peduncle) --> VL complex of the thalamus on the opposite side --> primary motor and premotor cortex

Question 33

The cerebrocerebellum projects to which deep cerebellar nuclei? Where does it project to from there? Why?

Answer 33

dentate nucleus; premotor cortex; motor planning

Question 34

The spinocerebellum projects to which deep cerebellar nuclei? Where does it project from there? Why?

Answer 34

interposed and fastigial nuclei; motor cortex and brainstem; motor execution

Question 35

The vestibulocerebrum projects to which nuclei? Then where does it go? Why?

Answer 35

vestibular nuclei; lower motor neurons in spinal cord and brainstem; for balance and vestibulo-ocular regulation

Question 36

Which lobe of the brainstem is involved in motor planning?

Answer 36

cerebrocerebellum

Question 37

Which lobe of the brainstem is involved in motor execution?

Answer 37

spinocerebellum

Question 38

Which lobe of the brainstem is involved in balance and vestibulo-ocular regulation (VOR)?

Answer 38

vestibulocerebellum

Question 39

How do cerebellar afferents get from the cortex to the cerebrocerebellum? Is this pathway crossed?

Answer 39

via pontine nuclei and MCP; crossed

Question 40

How do cerebellar afferents get from the olive to all parts of the cerebellum? Is this pathway crossed?

Answer 40

via the ICP (climbing fibers); crossed

Question 41

How do cerebellar afferents get to the vestibular nuclei, accessory cuneate nucleus, and Clarke's nucleus? Is this pathway crossed?

Answer 41

via the ICP; no!

Question 42

Describe the afferent pathway from the frontal/parietal cortex to the cerebellar cortex.

Answer 42

frontal/parietal cortex --> red nucleus --> inferior olive (cross to other side) --> inferior cerebellar peduncle --> cerebellar cortex/deep nuclei Or frontal/parietal cortex --> pontine nuclei --> middle cerebellar peduncle (cross to other side)--> cerebellar cortex/deep nuclei

Question 43

How do afferents get from the pontine nuclei to the cerebellar cortex/deep nuclei?

Answer 43

middle cerebellar peduncle

Question 44

How do afferents get from the inferior olive to the cerebellar cortex/deep nuclei?

Answer 44

inferior cerebellar peduncle

Question 45

Cerebellar cortex can also receive direct input from the (blank) and the (blank)

Answer 45

spinal cord; vestibular nuclei

Question 46

Where does spinal cord input to the cerebellar cortex come from?

Answer 46

Clarke's column (C8 and below)

Question 47

The origin of the dorsal spinocerebellar tract which carries information about muscle length, tension and velocity to the cerebellum from muscles below C7.

Answer 47

Clarke's column

Question 48

What does Clarke's column carry information about?

Answer 48

muscle length, tension, and velocity

Question 49

What levels does Clarke's column carry information from?

Answer 49

muscles below C7 (C8 and below)

Question 50

The upper limb equivalent for Clarke’s column carrying muscle information from C7 and above to the cerebellum over the ICP.

Answer 50

accessory cuneate nucleus

Question 51

What does the accessory cuneate nucleus carry muscle information from?

Answer 51

C7 and above

Question 52

What do Ia fibers from the muscle spindle carry info about?

Answer 52

length and rate of change

Question 53

What do Ib fibers from the GTO carry info about?

Answer 53

tension

Question 54

What do II fibers from the muscle spindle carry info about?

Answer 54

length

Question 55

Clarke's column is found in the dorsal horn between what spinal levels? What is it the beginning of?

Answer 55

C8 and L3; the beginning of the dorsal spinocerebellar tract

Question 56

Axons in Clarke's column receive muscle information which then ascends to the cerebellum in the ICP on the (blank)

Answer 56

dorsal spinocerebellar tract

Question 57

Above C8, muscle information travels to the (blank) nucleus instead of Clarke's

Answer 57

accessory cuneate nucleus

Question 58

What are the three major layers in the cerebellar cortex?

Answer 58

molecular layer purkinje cell layer granule cell layer

Question 59

What layer of the cerebellar circuitry is this? | purkinje cell dendritic tree with numerous parallel fiber endings

Answer 59

molecular layer

Question 60

What layer of the cerebellar circuitry is this? | Large cell bodies of Purkinje cells

Answer 60

Purkinje cell layer

Question 61

What layer of the cerebellar circuitry is this? | Granule cells, mossy fibers and climbing fibers entering cortex

Answer 61

granule cell layer

Question 62

Where are the deep cerebellar nuclei located?

Answer 62

in the white matter layer

Question 63

What are the two major excitatory inputs?

Answer 63

mossy fibers | climbing fibers

Question 64

Fibers that originate in: the contralateral pontine nuclei, the ipsilateral Clarke’s column and Accessory Cuneate nucleus, the vestibular nuclei and ganglion, and reach the cerebellar cortex where they excite granule cells. Any fiber that is not from the Olive

Answer 64

Mossy fibers

Question 65

All mossy fibers send an excitatory collateral to the (blank)

Answer 65

deep nuclei

Question 66

Fibers that originate in the contralateral inferior olive and reach all areas of the cerebellar cortex where they send an excitatory input to the purkinje cell dendrites after sending excitatory collateral to the depp nuclei

Answer 66

climbing fibers

Question 67

Incoming mossy and climbers fibers have an excitatory collateral to the (blank)

Answer 67

deep nuclei

Question 68

These are inhibitory to the deep nuclei and are the only way out of the cortex

Answer 68

purkinje cells

Question 69

What is the only way to get info out of the cerebellum?

Answer 69

turn the purkinje cells off momentarily and allow the deep nuclei to be driven by the mossy and climbing fibers

Question 70

All fibers projecting into the cerebellar cortex are (blank) (mossy fibers, climbing fibers & granule cell parallel fibers) that means the granule cells are (blank).

Answer 70

excitatory; excitatory

Question 71

All cells of the cerebellar cortex except the (blank) are inhibitory (Purkinje cells, stellate cells, basket cells and Golgi cells).

Answer 71

granule cells

Question 72

The deep cerebellar nuclei (not part of the cerebellar cortex) are (blank)

Answer 72

excitatory

Question 73

The only way out of the cortex is an inhibitory (blank) which must be turned off to allow the deep nuclei to fire.

Answer 73

purkinje cell axon

Question 74

What do lesions of the cerebellar hemisphere result in?

Answer 74

ipsilateral incoordination/ataxia

Question 75

What will a lesion in the RIGHT cerebellar hemisphere result in?

Answer 75

motor incoordination on the RIGHT side

Question 76

Will a lesion in the inferior or middle peduncle cause an ipsilateral or contralateral deficit?

Answer 76

an ipsilateral deficit

Question 77

Will a lesion in the superior cerebellar peduncle cause an ipsilateral or contralateral deficit?

Answer 77

it depends on if it is before or after the decussation A lesion of the RIGHT superior cerebellar peduncle before the decussation will also result in motor incoordination/ataxia on the RIGHT side. However, a lesion after the decussation of the superior cerebellar peduncle will result in CONTRALATERAL motor deficits

Question 78

If there was a lesion where the superior peduncles are crossing, what kind of deficit would this produce?

Answer 78

bilateral deficit

Question 79

A lesion in the superior peduncles after they have crossed sides would result in what kind of lesion?

Answer 79

ipsilateral

Question 80

Cerebellar lesions typically result in irregular uncoordinated movement called (blank)

Answer 80

ataxia

Question 81

What do spinocerebellar lesions usually result in?

Answer 81

unsteady gait (balance) and eye movement abnormalities

Question 82

What do vestibulocerebellar lesions usually result in?

Answer 82

problems with balance and eye movements

Question 83

When the cerebellum is damaged, what reflex fails to operate correctly?

Answer 83

VOR | *this was shown in monkeys who were given glasses to magnify or minify their vision

Question 84

What are the 3 distinct layers of the cerebellar cortex?

Answer 84

molecular layer purkinje layer granule layer

Question 85

Where is all output from the cerebellar cortex carried? What carries it?

Answer 85

into cerebellar white matter; | purkinje cells

Question 86

What is the ONLY output cell of the cerebellar cortex?

Answer 86

purkinje cells

Question 87

Are purkinje cells excitatory or inhibitory?

Answer 87

inhibitory

Question 88

What are the deep cerebellar nuclei?

Answer 88

fastigial globose emboliform dentate

Question 89

The outputs of cerebellar nuclei are all (blank)

Answer 89

excitatory

Question 90

Climbing fibers originate exclusively from the (blank). They ascend and provide a direct excitatory input to Purkinje cells.

Answer 90

inferior olivary complex

Question 91

(blank) originate from all other sources and ascend to form excitatory synaptic inputs to granule cells, which in turn excite the Purkinje cells via parallel fibers

Answer 91

mossy fibers

Question 92

Both climbing and mossy fibers are (blank)

Answer 92

excitatory

Question 93

IMPORTANT principle with cerebellar lesions is that deficits in coordination occur (blank) to the lesion

Answer 93

ipsilateral

Question 94

Each cerebellar hemisphere is concerned with the (blank) side of the body. Therefore, the right cerebellum controls the right side of the body, while the left cerebellum controls the left side of the body

Answer 94

ipsilateral

Question 95

Where do output axons from the dentate, globose and emboliform nuclei all cross?

Answer 95

at the decussation of the superior cerebellar peduncle