25-Motor6-Cerebellum

Question 1

components of cerebellar cortex (x3)

Answer 1

vermis, intermediate and lateral zones

Question 2

cerebellar nuclei (x4)

Answer 2

fastigial, globose, emboliform, dentate

Question 3

cerebellar peduncles

Answer 3

inferior, middle, superior

Question 4

cerebellum cortical layers (x3)

Answer 4

molecular, purkinje cell, and granular

Question 5

five intrinsic neurons in cerebellar cortex

Answer 5

• purkinje cells: only output neuron, inhibitory (GABA)
• granual cells: origin of parallel fiber system, excitatory (glutamate)
• stellate: inhibit Purkinje cells
• basket: inhibit Purkinje cells
• Golgi: inhibit granual cells
  These last three are all inhibitory interneurons, probably all use GABA, excited by parallel fibers

Question 6

basic cerebellar circuit (x4)

Answer 6

• mossy fibers -> granule cells -> Purkinje cells
• climbing fibers -> Purkinje cells
• Purkinje cells -> cerebellar nuclei and vestibular nucleus
• cerebellar nuclei -> many targets in CNS

Question 7

two major classes of inputs

Answer 7

• mossy fibber afferents
• climbing fiber afferents

Question 8

mossy fiber afferents originate from ___

Answer 8

various spinal and brainstem sites

Question 9

climbing fiber afferents originate from ___

Answer 9

contralateral inferior olive only

Question 10

mossy fiber afferents synapse on ___

Answer 10

granule cells (excitatory, glutamate)

Question 11

climbing fiber afferents synapse on ___

Answer 11

Purkinje cells, monosynaptically, excitatory

Question 12

mossy fiber afferents produce [simple/complex] spikes in Purkinje cells

Answer 12

simple

Question 13

climbing fiber afferents produce [simple/complex] spikes in Purkinje cells

Answer 13

complex

Answer 14

true

Answer 15

unknown

Question 16

Discharge rate of mossy fiber afferents

Answer 16

50-100 spikes/sec

Question 17

Discharge rate of complex fiber afferents

Answer 17

1-2 spikes/sec

Question 18

Cerebellar cortex is [ipsi/contra]laterally organized

Answer 18

ipsilaterally (unlike motor cortex)

Answer 19

false, they are orthogonal

Question 20

Inputs to inferior olive (x3)

Answer 20

• spinal projections
• cerebral cortical inputs
• red nucleus (feedback from cerebellum)

Answer 21

used to be common hypothesis, recently controversial, false?

Question 22

cerebellar functional divisions (x3)

Answer 22

• vestibulocerebellum
• spinocerebellum
• cerebrocerebellum

Question 23

Vestibulocerebellum:
location

Answer 23

flocculonodular lobe

Question 24

Vestibulocerebellum:
inputs via ___ fibers: (x4)

Answer 24

via mossy fibers
- semicircular canals
- otoliths
- visual info from retina and parietal/occiptal via pontine nuclei
- neck and trunk

Question 25

Vestibulocerebellum:
outputs: (x4)

Answer 25

• vestibular nucleus (medial and lateral) and fastigial nucleus
• medial vestibulospinal tract (which controls trunk/neck muscles)
• lateral vestibulospinal tract (controls limb muscles)
• gaze centers (controls eye movements)

Question 26

Spinocerebellum:
location

Answer 26

intermediate zones and vermis

Question 27

Spinocerebellum:
inputs via ___ fibers: (x2)

Answer 27

via mossy fibers
- spinocerebellar tracts (x3)
– from trunk/neck muscles
– dorsal spinocerebellar tract (DSCT)
– ventral spinocerebellar tract (VSCT)
- face somatosensory/proprioceptive inputs

Question 28

Spinocerebellum:
outputs (x1)

Answer 28

intermediate zone projects to globose and emboliform nuclei
- rubrospinal tract
- corticospinal tract

Question 29

Cerebrocerebellum:
location

Answer 29

cerebellar hemispheres (lateral zones)

Answer 30

true

Question 31

Cerebrocerebellum:
inputs via ___ from : (X2)

Answer 31

via pontine nuclei from
- sensory and motor cortices
- premotor and parietal cortices

Question 32

Cerebrocerebullum:
outputs via ___ to (x2)

Answer 32

via dentate nuclei to
- ventral lateral nucleus of thalamus to motor and premotor contex (corticospinal tract)
- prefrontal areas

Question 33

Cerebellar disorders:
disturbances of equilibrium / balance associated with ___

Answer 33

vestibulocerebellum

Question 34

Cerebellar disorders:
nystagmus associated with ___

Answer 34

vestibulocerebellum

Question 35

Cerebellar disorders:
loss of smooth pursuit associated with ___

Answer 35

vestibulocerebellum

Question 36

Cerebellar disorders:
loss of VOR suppression associated with ___

Answer 36

vestibulocerebellum

Question 37

Cerebellar disorders:
action tremor (voluntary) associated with ___

Answer 37

spinocerebellum

Question 38

Cerebellar disorders:
limb ataxia/dysmetria associated with ___

Answer 38

spinocerebellum

Question 39

Cerebellar disorders:
decrease in saccade accuracy associated with ___

Answer 39

spinocerebellum (posterior vermis)

Question 40

Cerebellar disorders:
hypotonia associated with ___

Answer 40

spinocerebellum

Question 41

hypotonia

Answer 41

decreased muscle tone

Question 42

Cerebellar disorders:
ataxia of fine movements associated with ___

Answer 42

cerebrocerebellum

Question 43

Cerebellar disorders:
decomposition of movements associated with ___

Answer 43

cerebrocerebellum

Question 44

Cerebellar disorders:
cognitive deficits (executive and nonmotor) associated with ___

Answer 44

cerebrocerebellum

Answer 45

true [see notes for more detail]

Question 46

Theories of cerebellum function (x5)

Answer 46

• regulation of reflex gains
• error - detection and error - correction
• motor learning
• timing of movements
• internal models of motor apparatus

Question 47

inverse dynamics model

Answer 47

calculates needed forces/torques from the desired trajectory

Question 48

forward internal model

Answer 48

predits future state of arm from the motor command and current state of arm

Answer 49

false (evidence that purkinje cells are not generating direct motor command)

Answer 50

true