Cerebellum and Motor Learning

Question 1

what is the cerebellum involved in, within the hierarchal sensorimotor system?

Answer 1

integration and providing fine-motor control

Question 2

properties of the cerebellum

Answer 2

massive cortical area with only 1 output layer, which is heavily folded

Question 3

what does the cerebellum exert influence on?

Answer 3

exerts influence on movement via motor and premotor cortex

also connects with brainstem and spinal cord

Question 4

cells within the cerebellum

Answer 4

Granule cells – 101,000,000,000

Purkinje cells – 15-30,000,000

Golgi, basket, stellate cells – 150-200,000,000

Nuclear cells – 5,000,000

Question 5

what do purkinje cells receive input from?

Answer 5

receive input from 200,000 parallel fibres and 1 climbing fibre

Question 6

what does the length and width of the cerebellar cortex reflect?

Answer 6

length - body mass
width - cognitive properties

Question 7

how many layers does the cerebral cortex have?

Answer 7

molecular layer (near the surface), Purkinje layer, and the granular layer

Question 8

what are the two inputs into the cerebellar cortex?

Answer 8

1. via mossy fibres
2. via climbing fibres

Question 9

input via mossy fibres

Answer 9

connect to granule cells, forming parallel fibres that connect to Purkinje cells

Question 10

input via climbing fibres

Answer 10

connects to one Purkinje cell with large connections within the energy

Question 11

what is the only output of the cerebellum?

Answer 11

Purkinje cells – these connect to the deep cerebellar nuclei, which connect via the Thalamus to the rest of the cortex

Question 12

what are the three sections of deep cerebellar nuclei?

Answer 12

lateral hemisphere

intermediate/paravermal hemisphere

vermal hemisphere

Question 13

lateral hemisphere

Answer 13

(output into denate nuclei, sending information to cerebro-cerebellum)

Question 14

intermediate/paravermal hemisphere

Answer 14

(reach interposed nuclei, sending information to spino-cerebellum)

Question 15

vermal hemisphere

Answer 15

(reaches fastigal nuclei, sending information to spino-cerebellum)

Question 16

inputs have an ______ effect on the cerebellum and purkinje cells have an ______ effect on the cerebellum

what does this mean?

Answer 16

excitatory effect
inhibitory effect

this means they cancel each other out, and the cerebellar nuclei does not do anythign

Question 17

what do cortico-cerebellar loops highlight?

Answer 17

the intricate connectivity between the Cerebellum and cortex, suggesting the Cerebellum is involved in more than just motor function

Question 18

damage to the cerebellum can cause:

Answer 18

hypertremia (overshooting movements)

intention tremors during actions

ataxia (loss of coordination and fine-motor control)

nystagmus (involuntary eye movements affecting balance and gait)

cerebellar affective disorder = impairs executive function, emotion, and personality

Question 19

wjhat does the “marr-albus” model of motor learning believe?

Answer 19

the cerebellum adapts motor behaviour by synaptic plasticity and LTD

Question 20

stages of the marr-albus model

Answer 20

1. synaptic plasticity between granule cells and Purkinje cells allows it to undergo LTD
2. LTD is triggered by simultaneous activity of parallel fibres and climbing fibres via mossy fibres, and error signals via climbing fibres.
3. LTD reduces Purkinje cell inhibition of cerebellar nuclei, and disinhibits the direct pathway.
    

Question 21

four examples of cerebellar learning

Answer 21

vestibular ocular reflex (VOR)
eye blink conditioning
skill learning
visuomotor recalibration

Question 22

VOR: what is the cerebellum involved in?

Answer 22

is involved in maintaining stable vision while the head is in motion, by adjusting the VOR gain to prevent retinal slips (blurred vision)

Question 23

VOR: what happens when retinal slips occur?

Answer 23

when retinal slips occur, they signal an error, and cause the Cerebellum to modulate the amount of gain applied.

If VOR gain is too weak, the retinal slip triggers LTD in Purkinje cells to stabilise vision.

Question 24

input and output of VOR:

Answer 24

input – vestibular system signal of head motion

output – modulation of direct path to ocular motor neurons

Question 25

eye blink conditioning: what does the cerebellum associate?

Answer 25

associates the conditioned and unconditioned stimulus, as they respectively reach Purkinje cells via granular and parallel fibres, and climbing fibres

Question 26

eye blink conditioning: what does simultaneous activation of pathways trigger?

Answer 26

triggers LTD in Purkinje cells, and allows the conditioned response to be elicited by the CS

Question 27

eye blink conditioning: how does the cerebellum facilitate learning?

Answer 27

facilitates learning by allowing associations to form between sensory cues and motor responses

Question 28

skill learning: what are complex spikes?

Answer 28

found in purkinje cells, they signal input from climbing fibres and reflect error signals

Question 29

skill learning: what does monitoring complex spikes allow?

Answer 29

allows us to track the Cerebellum’s response to errors during skill acquisition and learning

Question 30

visuomotor recalibration: what is the cerebellum crucial for?

Answer 30

crucial for responding to errors, as seen in providing compensatory adjustments to visual inputs when prism glasses are removed.

Learning is blocked by Cerebellar lesions

Question 31

what does the cerebellar prediction model enable?

Answer 31

enables the comparison of predicted sensory feedback with actual sensory feedback to update motor commands and minimise errors.

Question 32

what does the predictive mechanism of the cerebellum allow for?

Answer 32

rapid adjustments in movements, even before sensory feedback is received – crucial for fast actions and compensating for slow sensory feedback.

Question 33

what does feedback control rely on?

Answer 33

relies on sensory feedback to make corrections, leading to slower and jerky movements in patients with impaired Cerebellar function

Question 34

impairments in anterior lobe of cerebellum

Answer 34

failure in force-field paradigm

Question 35

impairments in posterior lobe of cerebellum

Answer 35

failure in visuomotor paradigm

Question 36

what predictive functions does the cerebellum perform?

Answer 36

performs the same predictive functions across several task domains

depends on the area of the cortex this is connected to

Question 37

what is crucial for anticipating future actions?

Answer 37

predicting sensory outcomes of motor commands

(predictive ability associated with larger cerebellar grey matter volume)

Question 38

what does cerebellar adaptation improve with?

Answer 38

age