T2 L5 Cerebellum & motor learning

Question 1

What is the role of the cerebellum?

Answer 1

Maintenance of balance & posture
Coordination of voluntary movements
Motor learning
Cognitive functions

Question 2

Describe the location of the cerebellum

Answer 2

Inferior to occipital & temporal lobes

Question 3

What forms the cerebellar cortex?

Answer 3

Grey matter

Question 4

What are the 3 lobes of the cerebellum?

Answer 4

Anterior
Posterior
Flocculondular

Question 5

What are the 3 subdivisions of the cerebellum?

Answer 5

Vestibulocerebellum
Spinocerebellum
Cerebrocerebellum

Question 6

What are the cerebellar nuclei?

Answer 6

Dentate
Fastigial
Interposed

Question 7

What is the dentate nucleus output?

Answer 7

Areas 4 & 6

Motor planning

Question 8

What is the fastigial nucleus output?

Answer 8

Medial descending system

Motor execution

Question 9

What is the interposed nucleus output?

Answer 9

Lateral descending system

Motor execution

Question 10

What is dysmetria?

Answer 10

Movement is not stopped in time (overshoot)

Question 11

What is dysnergia?

Answer 11

Decomposition of complex movements

Question 12

What is dysdiadochokinesia?

Answer 12

Reduced ability trying to perform rapidly alternating movements

Question 13

What is an intentional tremor?

Answer 13

Arises when trying to perform a goal-directed movement

Question 14

What is dysarthria?

Answer 14

Articulation incoordination. Incoordination in respiratory muscles, muscles of the larynx etc

Question 15

What is nystagmus?

Answer 15

Involuntary, rhythmical repeated oscillations of one or both eyes in any or all directions of view

Question 16

What can cause nystagmus?

Answer 16

Vestibular ocular pathway lesion

Question 17

What effect can a lesion in spinocerebellar have?

Answer 17

Gait ataxia

Disturbance of limb tone (hypotonia) & posture

Question 18

What effects can a lesion to cerebrocerebellum pathway cause?

Answer 18

Dysmetria
Dysnergia
Dysdiadochokinesia
Intentional tremor
Dysarthria

Question 19

What is gait ataxia?

Answer 19

Unsteadiness of walking

Question 20

Where do mossy fibres come from?

Answer 20

Spinal cord

Brainstem

Question 21

Where do climbing fibres come from?

Answer 21

Inferior olivary nucleus

Question 22

Where do the deep cerebellar nuclei output to?

Answer 22

Thalami
Vestibular nuclei
Red nucleus

Question 23

Describe the link with climbing fibres and purkinje cells

Answer 23

One climbing fibre to each purkinje cell with many synapses

Question 24

Describe the link with parallel fibres and purkinje cells

Answer 24

Many parallel fibres to each purkinje cell with one or few synapses

Question 25

What do the motor cortex & red nucleus generate signals via?

Answer 25

Corticopontinecerebellar tract

Question 26

What is proprioceptive feedback from muscles & joints via?

Answer 26

Spinocerebellum & vestibulocerebellum pathways

Question 27

What is the actual response compared with?

Answer 27

The desired response via cerebrocerebellum inputs from supplementary motor cortex & primary motor cortex to produce error signals

Question 28

Describe the feedback loop

Answer 28

Error signal is difference between desired input and output | Feedback comes from output

Question 29

Describe the feedforward loop

Answer 29

Movements that are too fast to be corrected by feedback are executed using predictions of their outcomes based on experience Advance information used to generate desired output & this fed forward to generate output

Question 30

What are error signals mainly derived from?

Answer 30

Sensory information

Question 31

What are error signals sent via?

Answer 31

Inferior olivary nucleus which then lead onto climbing fibres

Question 32

What are the genetic causes of cerebellar dysfunction?

Answer 32

Friederich's ataxia Spinocerebellar degeneration Ataxia-telengiectasia Von Hippel Lindau

Question 33

What are some acquired causes of symmetrical ataxia?

Answer 33

``` Alcohol Metabolic - B12, thyroid, coeliac Drugs - phenytoin Degenerative - familial, MSA Immune - paraneoplastic ```

Question 34

What arteries supply the cerebellum?

Answer 34

Superior cerebellar artery Anterior inferior cerebellar artery Posterior inferior cerebellar artery

Question 35

Why is ataxia less profound if the cerebellar cortex is involved?

Answer 35

It has some degree of plasticity