2. Cerebellum

Question 1

cerebellum

Answer 1

• no direct pathway to spinal cord, must go to brainstem first
• influences movement via connections with brainstem and cortical motor areas
• functions: sensorimotor integration (mediate movement in response to sensory stimulation), coordination, motor learning

Question 2

sensorimotor integration inputs and outputs

Answer 2

• inputs to cerebellum from all sensory systems: vision, audio, somatic sensation, vestibular, proprioception (muscle spindles, GTOs)
• inputs come from spinal cord, brainstem nuclei (inferior olive), and cerebral cortex via relays in pontine nuclei of brainstem
• outputs from cerebellum go to motor systems (via relays in brainstem and thalamus)

Question 3

true or false: structure and physiology at a single cell level of the cerebellum are very well-understood

Answer 3

true

Question 4

ataxia

Answer 4

• cerebellar lesion (head injury)
• lack of coordination
• errors in rate, range, force, direction of movement
• intention tremor (different from PD tremor), see tremor during movement as opposed to at rest in PD
• dysdiadochokinesis (inability to make rapidly alternating movements)
• lesions don’t affect sensation

Question 5

true or false: MS can affect cerebella input/output axons and result in cerebellar symptoms

Answer 5

true

Question 6

true or false: cerebellum can be affected in CP, with ataxia (if basal ganglia are affected there are involuntary movements)

Answer 6

true

Question 7

__ is a symptom of wernicke-korsakoff syndrome (WKS), a disease that results from __ often from alcohol addiction; there is degeneration of cerebellar __

Answer 7

ataxia, malnutrition (thiamine, vitamin B1 deficiency), neurons

Question 8

___ of neurons in the cerebellum can be a side effect of some seizure drugs (AEDs)

Answer 8

degeneration

Question 9

2 types of input fibers

Answer 9

mossy and climbing fibers

Question 10

most afferent fibers to the cerebellum form __ fibers, and come from the spinal cord and brainstem

Answer 10

mossy

Question 11

climbing fibers arise from a __ __, the inferior olive of the medulla

Answer 11

single nucleus

Question 12

each afferent fiber sends a branch to the __ __ and a branch to the __ __

Answer 12

deep nuclei, cerebellar cortex

Question 13

climbing fibers only synapse on which cells

Answer 13

purkinje

Question 14

how many layers and cell types does cerebellar cortex have

Answer 14

3 layers, 5 cell types (same cell types in the same synaptic relation to each other all over the cerebellar cortex, unlike cerebral cortex)

Question 15

5 cell types and their synaptic action (+/-)

Answer 15

granule cells +
purkinje cells -
golgi cells -
stellate cells -
basket cells -

Question 16

output of the cerebellar cortex is via __ cells (axons to deep nuclei)

Answer 16

purkinje

Question 17

true or false: the shape of the action potential spike is different between climbing and mossy fiber input

Answer 17

true

Question 18

complex spike

Answer 18

• climbing fiber input
• one large spike, multiple smaller spikes after

Question 19

simple spike

Answer 19

• mossy fiber input
• one large spike
• normal looking AP

Question 20

true or false: mossy fiber system is not very active

Answer 20

false: very active (50-100 simple spikes/second in purkinje cells)

Question 21

true or false: climbing fiber input is much less frequent than mossy but the frequency increases during motor learning

Answer 21

true

Question 22

mossy fibers mediate most of the ongoing work of the __, climbing fibers mediate __ __

Answer 22

cerebellum, motor learning

Question 23

output of cerebellum is via axons of __ __, projects back to the __ and __, relays to __ __ and to motor areas of the __ cortex

Answer 23

deep nuclei, brainstem, thalamus, spinal cord, cerebral