Lecture 13

Question 1

Cerebellum basic functions & 3 parts

Answer 1

Function: movement modification; primary: error detection & correction

PART
Cerebrocerebellum: cerebral cortex input
> highly skilled movement, esp. planning & execution
Spinocerebellum: spinal cord input (central, vermis)
> lateral regulates distal muscles, central regulates proximal
Vestibulocerebellum: brainstem vestibular nuclei input (flocculus/nodulus)
> movemnts to maintain posture/balance & vestibulo-occular reflex

Question 2

Cerebellar peduncles (3)

Answer 2

Superior: efferent
> neurons project to pMC, PMC, SC

Middle: afferent
> cell bodies in contralateral pontine nuclei

Inferior: afferent & efferent pathways
> afferents from vestibular nuclei, spinal cord, brainstem
efferents to vestibular nuclei & reticular formation

Question 3

(1) Function organization & projection of cerebellum

Answer 3

(see 13. 3)
midline
[FL & PL] |
↓ |
↓ [Pontine nuclei] –mCP→
↓ | [Cerebellar
↓ cortex deep nuclei]
↓ | ↑
[Red nucleus] →→ {[inferior olive] [spinal cord] [VN]}

Question 4

(2) Functional organization; words

Answer 4

Indirect projection: *cortex → pontine nuclei → middle cerebellar peduncle → cerebrocerebellum

• PMC, pMC (motor control)
  + somatic sensory cortex (sensory-motor integration)
  + visual motion regions of pPC (visuomotor coordination)

Question 5

(3) More orginization/projections

Answer 5

Vestibular nuclei & CNVIII → vestibulocerebellum & iCP
Proprioceptive info from face: mesencephalic trigeminal nucleux → spinocerebellum

Inferior olive → contralateral cerebellum via iCP
Inferior olive → modulatory, important for learning & memory

Question 6

Somatotopic representation of cerebellum

Answer 6

“fractured”: every body area represented multiple times
Remain ipsilateral

Question 7

Projections from cerebellum

Answer 7

4 deep nuclei:
dentate - cerebellum (largest)
intesposed (2x) - spinocerebellum
fastigial - spinocerebellum

Cerebrocerebellum → dentate nucleus → pMC
Spinocerebellum → intesposed/fastigial → PMC & brainstem
Vestibulocerebellum → VN → lower NNs in spinal cord/ brainstem
- planning, excecution, & balance/vestibulo-ocular, respectively

Question 8

Organization of deep nuclei

Answer 8

Mediolateral organization, like spinal cord
Fastigial → medial; axial & proximal muscles
Intersposed → lateral’ distal muscles, limbs

Question 9

Damage & ataxia

Answer 9

Ataxia: difficulty with smooth, coordinated movement

Cerebrocerebellum: coordination & visuomotor integration deficits
Vestibulocerebellum: direction of gaze & standing upright deficits
Spinocerebellum: walking difficulty

General: dysmetria, action/intention tremors, speech deficits
Inferior olive: motor learning
IPSILATERAL

Question 10

Mossy fibers

Answer 10

Synapse onto granuale cells
From many cortical & brain stem areas
Give rise to parallel fibers excitatory input onto Purkinje cells

Input to cerebellum

Question 11

Climbing fibers

Answer 11

Contact Purkinje cells directly
From inferior olice
Excitatory synapses onto Purkinje cells

Input to cerebellum

Question 12

Purkinje cells

Answer 12

ONLY CEREBELLAR OUTPUT CELLS
GABAergic inhibitory output
Projects to deep cerebellar nuclei
Modulates excitatory input from mossy/climbing fibers
(they also project to deep nuclei)