Cerebellum

Question 1

Functions of the cerebellum

Answer 1

Adjust output of UMN pathways

1) coordinates Rate, range, and force of outgoing motor movements
2) maintenance of posture
3) Planning and timing of complex movements (Piano, baseball etc)

DOES NOT act in awareness of sensory stimuli

Question 2

Inferior cerebellar peduncles

Answer 2

Cerebellar input (from ipsilateral cx) 
spinocerebellar tract, vestibular input and from olive, vestibular system

Question 3

Middle cerebellar peduncles

Answer 3

pontocerebellar fibers

input from the contralateral motor cx

Question 4

Superior cerebellar peduncles

Answer 4

cerebellar output

Question 5

Layers of cerebellum

Answer 5

Outer 
`1) Molecular layer (cell processes)
2) Purkinje Cell layer (1 cell thick) 
3) Granule cells (mostly granule cell bodies) 
4) Arbor Vitae (axons in and out)

Question 6

Mossy fibers

Answer 6

bring in the vast majority of afferents into the cerebellum

cell bodies in the spinal cord, (primary afferents in DRG) vestibular nuclei, pontine nuclei

Question 7

Output of cerebellar cx

Answer 7

PURKINJE NEURONS
GABA onto deep cerebellar neurons in the arbor vitae

modulate rate and force of ongoing movements in order to smooth them out

Question 8

Output of the cerebellum

Answer 8

Deep cerebellar nuclei

**have baseline activity that is decreased by Purkinje and increased by mossy fiber projections

Question 9

Climbing fibers

Answer 9

most powerful excitatory input onto the cerebellum

release aspartate 1000000x on a single Purkinje neuron

come from olivary nuc.
important for motor learning

Question 10

Flocculonodular lobe

Answer 10

vestibulocerebellum
input from vestibular apparatus
deep nuc= fastigial nuc
targets medial motor systems

functions in balance, posture, coordination of vestibular reflexes (VOR)

**mostly ipsilateral effects

Question 11

Lateral hemispheres

Answer 11

contains the cerebrocerebellum

input= motor cx (BA 4,6)
deep nuc=dentate
targets= Red nucleus, motor cx (4+6)

involved with initiation, planning, timing of complex motor movements

Question 12

corticopontine fibers

Answer 12

tracts carrying information from the primary motor cx to the pontine nucleus in the cerebrocerebllar pathway

run in anterior limb of internal capsule

Question 13

cuneocerebellar tracts

Answer 13

tracts carrying fine touch, proprioception, and vibration from UL to the spinocerebellar tracts

unconscious proprioception

Question 14

Posterior spinocerebellar

Answer 14

bring in fine touch/proprioception/ vibration from LL

unconscious proprioception

Question 15

tracts of the spinocerebellar tracts

Answer 15

rostral spinocerebellar
cuneocerebellar tracts (UL)
ant and post spinocerebellar (LL)
trigeminocerebellar tract

Question 16

Vermis

Answer 16

Spinocerebellar
peripheral input= spinocerebellar tracts (axial and proximal postural mm.)

nuc=fastigial
targets=medial motor systems
function= axial and prox motor control

adjusts ongoing movements

Question 17

Paravermal regions

Answer 17

spinocerebellar tracts (distal limbs)

nuc= interposed nuc
target=lateral motor systems

distal motor control to adjust ongoing movements

Question 18

cerebellar lesions

Answer 18

deficits in coordination are ipsi to lesion

motor ataxia 
dysrythmia 
dysmetria 
intention tremor 
dysdiadochokinesia

Question 19

Midline lesions

Answer 19

unsteady gait (truncal sway)
wide based stance
uncoordianted eye movements

Question 20

lateral lesions

Answer 20

ataxia of limbs (appendicular ataxia)

past pointing
dysdiadochokinesia

Question 21

SCA lesion

Answer 21

would affect the vermis and lateral cerebellar hemispheres

Question 22

AICA lesion

Answer 22

most of the anterior portion, cerebellar peduncles would be lost

Question 23

PICA

Answer 23

nodulus would be lost

Question 24

Decorticate posturing

Answer 24

Loss of LMNs or UMNs in the corticospinal tract but rubrospinal tract remains intact so the arms and forearms are held in flexion

or…no modulation of the brainstem UMNs by the corticospinal system

Question 25

decertebrate posturing

Answer 25

if the rubrospinal tract and LMNs/UMNs of corticospinal tract are damaged