Hirsch - Cerebellum Flashcards

1
Q

function of cerebellum

A

compare motor plans with physical execution

make adjustments to keep movements coordinated, fluid, and on target

also involved in motor learning

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2
Q

cerebellar disorder

  1. ataxia
A

reeling, wide based gait

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3
Q

cerebellar disorder

  1. decomposition of movement (general)
A

inability to correctly sequence fine, coordinated acts

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4
Q

cerebellar disorder 2.1. dysarthria

A

inability to articulate words correctly with slurring and inappropriate phrasing

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5
Q

cerebellar disorder 2.2. dysdiadochokinesia

A

inability to perform rapid alternating movements

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6
Q

cerebellar disorder 2.3. dysmetria

A

inability to control range of movement (hypo or hypermetria)

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7
Q

cerebellar disorder 2.4. hypotonia

A

decreased muscle tone

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8
Q

cerebellar disorders 2.5. nystagmus

A

involuntary, rapid oscillation of the eyeballs in a horizontal, vertical or rotary direction with the fast component maximal toward the side of the cerebellar lesion

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9
Q

cerebellar disorders 2.6. tremor

A

rhythmic, alternating, oscillatory movement of a limb as it approaches a target (intention tremor) or of proximal musculature when fixed posture or weight bearing is attempted (postural tremor)

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10
Q

arbor vitae

A

whitematter of cerebellum

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11
Q

functional divisions of cerebellar cortex

A

cerebrocerebellum (neocerebellum)

spinocerebellum (paleocerebellum)

vestibulocerebellum

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12
Q

cerebrocerebellum

A

lateral

phylogenetically new

receive input from contralateral cerebral cortex

regulate complex sequence of movement including speech

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13
Q

spinocerebellum

A

paramedian and median (vermis zone)

phylogenetically older than neocerebellum

receive input from spinal cord

somatotopic organization

* paramedian: regulate distal muscles

* median: regulate proximal muscle and some eye movements

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14
Q

vestibulocerebellum

A

caudal and inferior lobes

phylogenetically ancient

receives input from vestibular nuclei (in brainstem)

regulate posture and balance including eye movements

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15
Q

deep cerebellar nuclei

A

dentate

interposed

fastigial

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16
Q

dentate nucleus

A

input from cerebrocerebellar zone

projects to:

  1. contralateral premotor cortex
  2. association cortices of frontal lobe involved in planning movement
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17
Q

Interposed nucleous

A

globose nucleus + emboliform nucleus

input from spinocerebellar zone

projects to:

contralateral motor cortex (aid executing movement)

18
Q

Fastigial nucleus

A

input from spinocerebellar zone

projects to:

upper motor neurons (in ipsilateral brainstem)

to aid executing movement

19
Q

vestibulocerebellum

A

project to vestibular nuclei

NOT to cerebellar nuclei

20
Q

cerebellar peduncles

*afferent connection arrives

*efferent connection exits

A

fiber bundles carrying inputs and outputs

  1. superior (brachium conjuntivum)
  2. middle(info to cerebellum)
  3. Inferior (restiform body
21
Q

superior peduncles - cerebellar

A

efferent pathway exiting from deep cerebellar nuclei

22
Q

middle peduncles

A

afferent pathway carrying information from the cortex via the pons

23
Q

inferior peduncle

A

mixed;

afferent come from brainstem and spinal cord

efferent exit from vestibulocerebellum

24
Q

know picture in (7/16) for structures associated with cerebellum

A

medial premotor cortex and primary motor cortex

VA/VL complex of thalamus

cerebellar cortex

deep cerebellar nuclei

pontine nuclei

vestibular nuclei

inferior olive

external cuneate nucleus

dorsal nucleus of Clarke

25
Q

Inputs to cerebellum

A
  1. from cerebral (frontal/parietal) cortex:

project to pontine nuclei (ipsilateral)

controls contralateral side of the body

  1. cerebellar hemisphere:

receive ascending input from ipsilateral side of body

control movements on the same side of the body

** pathway from cerebral cortex to cerebellum cross at middle cerebellar peduncle

26
Q

Ascending outputs of the cerebellum

A

cerebrocerebellum -> premotor cortex via dentate (motor planning);

part of it spreads to red nucleus parvocellular

spinocerebellum -> motor cortex via interposed nuclei (motor execution)

27
Q

descending outputs of the cerebellum

A

spinocerebellum -> brainstem via fastigial nucleus (motor execution)

vestibullocerebellum -> project directly to vestinular nuclei (motor adjustment, balance)

28
Q

Cytoarchitecture of the cerebellum

three layers of cerebellar cortex from out to in

A
  1. molecular layer (ML) - dendrites of purkinje cells and axons of granule cells (parallel fibers)
  2. Purkinje cell layer (PL) - purkinje cells and basket cells
  3. granule cell layer (GL) - granule cells have “claws”
29
Q

cerebellar circuits

climbing fibers

mossy fibers

A

climbing fibers - comes from inferior olive

mossy fiber - comes from pontine nuclei

30
Q

climbing fiber and purkinje cell

A

purkinje cell receive input from a single clibing fiber (from inferior olive) (ONE)

fires “complex spike” in response to input from a clibing fiber

31
Q

inferior olive

A

makes single climbing fiber to purkinje cells

receives input from cerebral cortex, spinal cord, and “red nucleus”

32
Q

mossy fiber and purkinje cell

A

come from pontine nuclei

synapse with granule cells

purkinje cell receives hundreds of thousands of inputs from parallel fibers (MANY)

purkinje cells fire “simple” spikes in response to input from parallel fibers

33
Q

pontine nuclei

A

make mossy fibers to granulle cell (parallel fibers)

relay input from cerebral cortex, spinal cord and “vestibular nuclei”

34
Q

motor learning: cerebellum can learn to compensate changes in the status quo

A

ex. normal vestibulo-ocular reflex (VOR) vs. VOR out of register using minifying glasses

—> VOR gain reset by moving eyes in smaller distance to compensate

movement adjusts to the vision

35
Q

cerebellar loops

A
  1. direct loop (deep excitatory)
  2. cortical inhibitory loop
  3. climbing fiber loop
36
Q

direct loop; deep excitatory

A

from mossy fibers

(afferent information)

to deep cerebellar nuclei

“motor system - a reflex pathway”

37
Q

cortical inhibitory loop

A

from mossy fibers

via parallel fibers

to granule cells

to purkinje cells

to ddep cerebellar nuclei and motor system

“to fine-tune reflexes”

38
Q

climbing fiber loop

A

detect errors

correct them over longterm

“motor learning loop”

39
Q

motor learning

A

climbing fiber loop & complex spike

important

40
Q

climbing fibers derive from ______

mossy fibers come from ______

A

climbing fibers derive from inferior olive

mossy fiber come from pontine nuclei

41
Q

know how to draw (16/16)

A
  1. planning and programming

(sensory association cortex, basal ganglia, lateral hemisphere of cerebrocerebellum ===>premotor cortical area)

  1. movement

( ==> motor cortex, vermis and intermmediate hemisphere of spinocerebellum)

  1. feedback signals

(vermis and intermediate hemisphere of spinocerebellum)