CB Flashcards

1
Q

What are the general functions of the cerebellum?

A
  • regulate equilibrium
  • muscle tone and posture
  • motor coordination for voluntary mvmts (modifies motor programs in response to environmental changes)
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2
Q

What are the two main fissures of the cerebellum and what do they separate?

A

posterolateral fissure: separates flocculunodular area from rest of cerebellum

primary fissure: anterior/posterior divisions

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3
Q

What are the deep nuclei of the cerebellum?

A

dentate
interposed (emboliform, globose)
fastigal

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4
Q

Inferior cerebellar peduncle restiform body

A

inputs from spinal cord, brainstem

monitors muscle and limb mvmt

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5
Q

ICP juxtarestiform body

A

interconnects vestibular nuclei and cerebellum

imp for head/eye mvmt

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6
Q

middle cerebellar peduncle

A

largest, located lateral to pons

gets afferents from: CONTRA basis pontis
relays motor signals from cerebral cortex to cerebellum

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7
Q

superior cerebellar peduncle

A

mostly EFFERENT fibers

fibers go to red nucleus, thalamus

DECUSSATES

exception to “outflow from SCP” rule: anterior spinocerebellar tract uses SCP to enter cerebellum

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8
Q

How is the cerebellum somatotopically arranged?

A

fractioned somatotopy

dif parts of body show up multiple dif places

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9
Q

What is the general pattern for how info from the spinal cord and brainstem get into the cerebellum?

A
  1. info enters from SC, BS on mossy fibers via ICP and MCP
  2. synapse in granule layer
  3. synapse in molecular layer on purkinje cells (PKC)
  4. synapse in deep cerebellar nuclei
  5. go to either:

a) red nucleus and thalamus (VL) via SCP
b) vestibular nuclei via ICP

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10
Q

What is the general pattern for how info from the inferior olivary nucleus (ION) gets into the cerebellum?

A
  1. info from ION leaves on climbing fibers via ICP
  2. synapse in molecular layer on PKC
  3. synapse in deep cerebellar nuclei
  4. go to either:

a) red nucleus and thalamus (VL) via SCP
b) vestibular nuclei via ICP

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11
Q

What are the three layers of the cerebellar cortex and are they uniform throughout?

A

yes uniform

from top to bottom:
molecular layer
PKC layer
granule layer

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12
Q

Do climbing fibers from ION synapse in granule layer?

A

no

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13
Q

What are the excitatory cells of the cerebellar circuit?

A

mossy fiber

climbing fiber

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14
Q

What are the inhibitory cells of the cerebellar circuit?

A

stellate
basket
golgi
PKC

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15
Q

What do stellate and basket cells do?

A

inhibit PKC

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16
Q

What do golgi cells do?

A

inhibit granule cells

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17
Q

What happens once mossy fibers excite a group of granule cells?

A
  1. 100s of PKC are excited via parallel fibers
  2. PKC inhibit neurons in deep nuclei
  3. weakly facilitated PKC are edges of activated zone are turned off by stellate, basket cells to focus signal
  4. golgi cells in granule layer turn off initial signal
18
Q

Do mossy and climbing fibers send collaterals to deep nuclei before the axon enters the cerebellar cortex?

19
Q

Where do PKC axons end?

A

deep nuclei of cerebellum

20
Q

What CP does the anterior spinocerebellar tract use?

A

SCP

note: AST crosses midline 2x

21
Q

What CP does the posterior spinocerebellar tract use?

22
Q

What CP does the cuneocerebellar spinocerebellar tract use?

23
Q

What CP does the pontocerebellar tract use

24
Q

what CP does the olivocerebellar tract use

A

ICP

aka climbing fibers

25
Q

what CP does the trigeminal nerve use

26
Q

how does the olivocerebellar tract work

A
  • sensorimotor cortex sends info to IPSI olivary nuclei
  • olivocerebellar tract sends info to CONTRA cerebellar cortex thru ICP (these are climbing fibers)
  • climbing fibers branch, only one climbing fiber synapse per PKC
27
Q

what is the main function of the olivocerebellar tract

A

involved in learning new motor skills

at rest: PKC complex spikes
with training: PKC simple spikes

28
Q

what is the red nucleus up to

A

inputs: info from cerebral cortex descending to olive and info from cerebellum ascending to thalamus
output: inhibitory to IPSI olivary nucleus

basically can sense a mismatch between info leaving/going into cerebellum and can correct for it

29
Q

How does the majority of info leave the cerebellum

30
Q

What are the longitudinal zones of the cerebellum? What nucleus is associated with each?

A

(most medial)

vestibulocerebellum
-fastigial nucleus

spinocerebellum
-interposed nucleus

pontocerebellum
-dendate nucleus

31
Q

Vestibulocerebellum: location, input, output, function

A

location: flocculonodular lobe, vermis
input: vestibular system
output: fastigial and vestibular nucleus
function: control eye mvmts in response to head, maintain balance

32
Q

how does info leave the vestibulocerebellum

A
  • from fastigial nucleus: bilateral projection to vestibular nuclei via ICP
  • from vestibular nucleus control eyes thru MLF
  • lateral vestibular nucleus mediates balance
33
Q

Spinocerebellum: location, input, output, function

A

location: mostly paravermal area
input: spinal cord, brainstem (CN V)

output: interposed nucleus to:
- red nucleus
- VA/VL of thalamus to motor areas of cortex

function: posture, gait, coordination of trunk nd limb

34
Q

how does info leave the spinocerebellum

A
  • from interposed nucleus, leave thru SCP
  • terminate in:

CONTRA reticular formation (regulate posture and locomotion)

CONTRA red nucleus (motor learning)

VA/VL thalamus

35
Q

pontocerebellum: location, input, output, function

A

location: lateral cerebellum
input: motor cortex, basilar pons (MCP)

output: dentate nucleus to:
- red nucleus to ION
- VA/VL of thalamus to all motor areas

function: planning timing of mvmts (esp hand), coordination of speech

36
Q

how does info get out the pontocerebellum (neo)?

A
  • info from dentate nucleus, forms dentatorubrothalamic tract (this is the majority of the SCP)
  • SCP decussates
  • sends collaterals to red nucleus (to ION)
  • synapses in VL of thalamus, then onto motor areas of the cortex
37
Q

Describe the cerebella-thalamo-cerebro-cortical (CTCC) loop

A

Starting at cerebellar cortex:

  • info from cerebellar cortex to deep cerebellar nuclei
  • info from deep cerebellar nuc crosses midline, synapse in thalamus
  • from thalamus, synapse in cerebral cortex
  • from cerebral cortex, synapse in basilar pons
  • from basilar pons, synapse back at cerebellar cortex

**if spinal cord included: info goes from cortex to spinal cord, then back into cerebellar cortex

38
Q

What side of the body does one half of the cerebellum control?

A

IPSILATERAL

39
Q

What symptoms would accompany a lateral hemisphere injury?

A

arms and speech fucked up

intention tremor
dysdiadochokinesia (rapid alt mvmts)
dysmetria (finger to nose test)
dysarthria (uneven, explosive phonation)

40
Q

What symptoms would accompany a vermal injury?

A

trouble with posture

truncal ataxia
gait ataxia

41
Q

What symptoms would accompany a vestibulocerebellar injury?

A

nystagmus (back and forth eye mvtms)

42
Q

What happens if you have a stroke in your cerebellum?

A

cognitive defects, decrease reasoning power, inattention, patchy memory

dulling of emotional responses, aberrant emotional behaviors