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)

Question 30

[True/false]: cerebrocerebellum is largest part of cerebellum

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

Question 45

[True/false]: there are many types of synatic plasticity in cerebellum

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

Question 49

[True/false]: Purkinje cells are modulated in relation to forces or muscle activity

Answer 49

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

Question 50

[True/false]: Cerebellar patients fail to learn predictions yet respond to feedback

Answer 50

true