Cerebellum I & II

Question 1

Cerebellum development

Answer 1

-develops as the dorsal part of metencephalon
-attached to pons

Question 2

Ventral aspect of Cerebellum

Answer 2

-acts as a roof of the 4th ventricle
-lateral apertures allow for the flow of CSF into the subarachnoid space, which means CSF can be found external to the brain/spinal cord

Question 3

Cerebellar lesion movement signs

Answer 3

-goofy, choppy movements
-can’t coordinate movements. Have inappropriate movements.
-head tremor

Question 4

Common virus causing cerebellum lesion in cats

Answer 4

-panleukopenia

Question 5

Cerebellar peduncles

Answer 5

*axon tracts in/out of the cerebellum
1.Rostral
2.Middle
3.Caudal

Question 6

Information/pathways going to cerebellum

Answer 6

-proprioceptive information from spinocerebellar tracts of spinal cord into cerebellum
-brain stem nuclei leave brainstem and go to LMN in spinal cord BUT a copy of brainstem nuclei goes to cerebellum which allows for slight changes in movement (eg. Walking up hill vs. walking on flat ground)
-Cortical UMNs synapse on pontine nucleus and will supply copy to cerebellum so that it is aware of movements

Question 7

Neurons from the cerebellum

Answer 7

-involved in modulating movements, sending signals to cortical UMNs and brainstem
>tells body “I know you want to eat from bowl, but bowl is farther away than originally thought”

Question 8

Cerebral grey matter vs. cerebellar grey matter

Answer 8

-much tighter folds to increase SA/neuron capacity but it is confined to a small space

Question 9

Vestibulocerebellum (flocculonodular node) input, output and function

Answer 9

-input for CN 8
-Output for vestibular nuclei in medulla
-function-vestibular system: maintain upright posture of head and body

Question 10

Cerebrocerebellum (cerebellar hemispheres)

Answer 10

-input for cerebral cortex via pontine nucleus
-output for cerebral cortex via thalamus
-Function- higher order movements (planning, timing, learning/muscle memory)

Question 11

Spinocerebellum (cerebellar vermis)

Answer 11

-input spinocerebellar tracts (caudal peduncle) and brainstem UMNs
-output for brainstem UMNs
-function- proper coordination of limb muscles and movements

Question 12

Spinocerebellum input specific function

Answer 12

-proprioceptive tracts and copy of motor movement commands sent to spinal cord by brainstem nuclei

Question 13

Spinocerebellum output specific function

Answer 13

-corrections to adjust motor movements to make sure they are appropriate
Goes to brainstem UMNs

Question 14

Cerebellum neurons

Answer 14

• the cerebellum does not contain UMNs
  > no paresis/paralysis caused by lesions

-the cerebellum does not initiate movements (only coordination and modifications to motor movements)
> lesions causes ataxia, but it will not ability to move

Question 15

Three characteristics of motor movements

Answer 15

1.rate
2. range
3. force
**cerebellum is responsible for ensuring that these characteristics are appropriate for the circumstance AND will adjust in real-time to changes in environment

Question 16

Lesions of cerebellum

Answer 16

1.ataxia= cerebellar ataxia (exaggerated/choppy gait)
2.proprioceptive deficits= hopping, knuckling are abnormal
>NOTE: these animals will never lose proprioception, but they will be exaggerated!
3.increased muscle tone, especially of extensor muscles (occurs because UMNs are not inhibited by cerebellum resulting in UMNs sending increased signal to LMN=increased tone)
4. Not paralyzed
>no paralysis, no paresis because UMN are intact
5.Tremors (will often worsen with movements- intention tremor)= dysmetria
>True tremor is a cerebellum sign most of the time. Animal trying to do movement but not sure how to do it because cerebellum damage
6.Loss of menace response
>menace pathway goes through cerebellum, so needed for control.
7. Truncal ataxia= broad based stance (with truncal sway)
>due to animals being aware that they are off balance
8.Vestibular disease signs
>head turn, falling to one side, rolling,
>ear infections
9. Opisthotonus- hyperextension of body/head/limbs
>severe lesions (can be cortical, brainstem or cerebellar lesions)

Question 17

Menace response

Answer 17

-learned response involving CN II, animal will see something coming towards them, send signal to brain and cerebellum and then they will blink (CN VII). Young animals won’t have learnt behaviour yet.

Question 18

Hypermetria

Answer 18

-hypermetric gait can be seen in both a cerebellar lesion and C1-C5 lesion
Cerebellar damage: slamming everything down, choppy excessive movements
Spinal C1-C5 segment damage: smooth, excessive movements

Question 19

Ataxia movement due to cerebellar lesion

Answer 19

-dysmetria, specifically hypermetria
◦ too fast
◦ too forceful
◦ too far
-truncal sway

Question 20

Bilateral cerebellar lesion

Answer 20

-widespread, diffuse disease

Question 21

Focal lesion of cerebellum or brainstem

Answer 21

-will get ipsilateral signs
-sometimes bilateral signs

Question 22

Contralateral signs

Answer 22

-think forebrain, not cerebellar

Question 23

Causes of cerebellar lesions

Answer 23

-neoplasia
-infections (fungal, viral, bacteria)
-metabolic disorders/toxins
-abscesses
-increased ICP
-congenital malformations/hypoplasia/atropy
-caudal/ventral skull fractures
-herniation
-trauma (cerebral edema, hemorrhage)
-ischemia/stroke
-high altitude cerebral edema