The Cerebellum Flashcards

1
Q

What is the function of the cerebellum?

A

Motor learning
Coordination of movements (timing, force)
Maintenance of balance and posture
Cognitive functions

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2
Q

What are the entryways and exits to the cerebellum?

A

Inferior peduncle - afferents from medulla
Middle peduncle - afferents from pons
Superior peduncle - efferents to midbrain

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3
Q

What are the 3 different nuclei of the cerebellum? Medial to lateral

A

Fatigial nucleus
Interposed nucleus
Dentate nucleus

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4
Q

Briefly, What are the outputs from the fatigial nucleus/

A

Output to vestibular nuclei and medial descending tracts for posture and movement execution

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5
Q

Briefly, what is the output of the interposed nucleus/

A

To lateral descending tracts

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6
Q

Briefly, what is the output of dentate nucleus?

A

Output to the thalamus (VA+VL) to cerebral cortex

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7
Q

What are the lobes of the cerebellum?

What separates them?

A

anterior
Posterior
Flocculonodular (most primitivel

Anterior - posterior = primary tissue
Posterior - flocculonodular = posteriorlateral fissue

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8
Q

What are the threes functional zones of the cerebellum?

A

Vesitubulocerebellum
Spinocerebellum
Cerebrocerebellum

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9
Q

Breifly, what is the function of the different functional zones

A
Vestibulocerebellum = balance
Spinocerebellum = error correction
Cerebrocerebellum = movement planning
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10
Q

What lobes form the spinocerebellum?

A

Anterior lobe, Vermal region and medial posterior lobe

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11
Q

What deep nuclei are associated with outputs of the spinocerebellum?

A

Interposed

Fastigial

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12
Q

Where does the interposed N. project to? How do they act ipsilaterally?

A

Goes via the superior peduncle to the contralateral red nucleus (decussate). Inputs to the rubrospinal tract which decussates again (lateral descending tract). Thus interposed outputs at ipsilaterally

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13
Q

Interms of outputs from the spinocerebellum to the fastigial N, where do these project to?

A

Project to the reticular formation and form the medial descending tracts

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14
Q

What inputs into the spinocerebellum?

A

The spinocerebellum tracts, reticular formation and vestibular nuclei via the inferior peduncle

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15
Q

What nuclei is associated with outputs from the cerebrocerebellum?

A

The dentate nucleus

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16
Q

What lobes form the functional zone the cerebrocerebellum

A

The lateral parts of the posterior lobe

17
Q

Where is the vestibulocerebellum located?

A

In the flocculonodular lobe

18
Q

What inputs into the cerebrocerebellum?

A

Inputs from the motor cortex areas via the pontine nuclei (enter cerebellum via middle peduncle). This contains information regarding the motor plan

19
Q

What is unique about the inputs and outputs of the cerebellum?

A

They are all ipsilateral

20
Q

Where do outputs from the cerebrocerebellum go?

A

To dentate nucleus (synapse here)
Onto the thalamus (synapse)
To motor cortex. M1, SMA and PMC receive inputs from dentate gyrus

21
Q

Where do inputs from mossy fibres project from?

A

The spinal cord
Reticular nuclei
Pontine nuclei
Depending on what functional zone they are in they contain information regarding proprioception, muscle load, desired muscle movements)

22
Q

The inferior olive sends error signals to the PC’s via climbing fibres. But what inputs into the inferior olive?

A

CF fire when unexpected event in movements occur
Receive inputs from spinal cord (cutaneous afferents, joint afferents, muscle spindles)
And cerebral cortex

23
Q

What occurs in the cerebrocerebellum?

A

Planning, organisation + co ordinating aspects of movements

24
Q

What projects into the vestibulocerebellum?

A

Inputs from the vestibular nuclei

25
Q

Where does the outputs of the vestibulocerebellum project to?

A

The vestibular nuclei and the vestibular spinal tracts (controls balance and eye movements)

26
Q

What is the role of basket/stellar cells?

A

PF will stimulate basket cells and stellate cells. These will then cause lateral inhibition of neighbouring PC to cause a clear contrast between excitatory and inhibitory signalling

27
Q

The role of the spinocerebellum is to function as an error corrector. How does it do this?

A

Acts as a smiths predictor
Will predict where limb is in space in the time taken for error signal to be processed and will correct for predictive error (i.e. Correct for the error of where the limb currently is) instead of the error which initiated the error signalling. If it did not error for the predictive error the error correction would not be appropaote as the limb will have moved

28
Q

When does the dentate nucleus fire?

A

Before movement

29
Q

What occurs on cooling the dentate nucleus?

A

Increases time taken for motor cortex output compared to controls and causes movement decomposition and loss of predictive movements

30
Q

When do the interposed nuclei fire?

A

After movement onset and is related to velocity error correction

31
Q

When does the fastigial nuclei fire?

A

After movement onset and is related to force error correction

32
Q

Name some signs of cerebellar lesions

A
Dysdiadochokinesia 
Ataxia of gait
Nystagmus
intention tremor
Spacing/slurred speech
Hypotonia
Writers cramp
Decomposition of movement
Dysmetria
Loss of motor memory
33
Q

What is dysdiadochokinesia?

A

Inability to perform rapidly alternating movements

34
Q

What is an ataxic gait?

A

Wide based staggering gait
Cannot walk toe to toe
(Vestibulocerebellum lesion)

35
Q

What is an intention tremor?

A

More pronounced tremor towards the end of target directed movements

36
Q

What is meant by the decomposition of movement?

A

Movement will be split up into individual parts rather tan coordinated

37
Q

What is dysmetria?

A

Overcompensation in speed (interposed N) and force (fatigial n) leading to overcorrection

38
Q

What is writers cramp?

A

When writing the co ordinated activation of the agonist and antagonist muscle is important for writing. If cerebellar lesion lack of coordination means they will be active together = writers cramp