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Flashcards in Unit III Deck (48)
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1

Cerebellum in general

10% of volume, 50% of neurons
falx cerebelli separates the two hemisphere
tentorium cerebelli separates from brainstem
embryologically from the pons

Does NOT initiate movement, coordinates it
cog/language/attention function
folds of terminal folia

2

Superior cerebellar peduncles

receives axons ventral spinocerebellar & tectum

efferent fibers to the midbrain

3

Middle cerebellar peduncles

receives axons from contralateral cortex through the pons

afferent fibers from pontine nuclei

4

Inferior cerebellar penduncles

smallest but most complex cerebellar penduncle
2 way afferent and efferent

dorsal/cuneo spinocerebellar and vestibulocerebellar

5

3 cerebellar lobes

Anterior lobe--> receives from SC = spinocerebellum

Posterior lobe --> associated with cortex = neocerebellum

Flocconodular lobe --> oldest receives from vestibular=vestibulocerebellum

6

Vermis division afferent/efferent and lesion sign

receives somatosensory input from SC

projects to fastigial nuclei

lesion= monkeys falling over to ipsilateral side

7

Intermediate division afferent/efferent and lesion sign

receives from red nucleus input from brainstem/SC

projects to interpositus nuclei

lesion= rigidity and difficulty moving limbs, intentional tremors

8

Lateral division afferent/efferent and lesion sign

receives from motor association cortices

projects to dentate nuclei and premotorcortex

Ballistic movement

Multijoint movement
Motor movement learning
Timing movement
Cognitive movement

9

Somatotopy of cerebellum

LE superficial
Neck/trunk deep

10

Final division

flocconodular node = head and neck balance control

11

Main input/ouput of cerebellum

input: cortex (initiating and planning movement) & somatosensory cortex (real time error detection)

output: Deep cerebellar nuclei

12

Molecular layer of folia (most superficial)

contains:
axons (parallel fibers) of the granules
dendrites of purkinje fibers
golgi neurons
basket cells

13

Purkinjie layer of folia (middle layer)

single layer of output to DCN

14

Granular layer of folia (deepest layer next to white matter)

contains:

granules and mossy fibers

15

Cells within the folia

Purkinje cells: inhibitory (GABA) to the DCN

Basket cells: inhibitory (GABA) to Purkinje cells

Granule cells: excitatory (GLUT) to Purkinje cells

Mossy fibers: excitatory )GLUT) to granule cell
climbing fibers: excitatory (GLUT) inferior olivary nuclei to Purkinje dendrites

Golgi fibers (inhibitory GABA) to interneurons to granule

16

Deep cerebellar Nuclei in general

only output of cerebellar

receives excitatory from other cells

4 different DCN receives 4 different Purkinje signaling from 4 different divisions

lesion to the DCN= complete lesion to cerebellum

17

DCN projection

dentate & interpositus (globose/emboliiform) project to the contralateral red nucleus and thalamus via the superior cerebellar peduncles

fastial nuclei project to the ipsilateral RF/Vestibular via the inferior cerebellar peduncles

18

Function Cerebellum

Coordination- timing and pattern

Balance and Equilibrium- conjunction of propioceptive and vestibular input

Postural stability- regulation of mm tone from SC and brainstem

19

Localizing the hemisphere by lesion of cerebellum

cerebrocerebellum- lateral (appendicular ataxia)
spinocerebullum- medial (appendicular ataxia)
cerebellar vermis (axial and gait ataxia)
vestibulocerebellum- flocconodular node (axial and gait ataxia)

20

Lateral hemisphere of Cerebellum function and tract influence

motor planning of fine motor and tone

influenced: lateral corticospinal tract

21

Intermediate hemisphere of cerebellum function and tract influence

distal limb evolving error detection from proprioceptie input

influenced: lateral corticospinal tract and rubrospinal tract

22

Vermis Hemisphere of cerebellum function and tract influence

proximal limb posturing/control
tone regulation
gait/locomotion adjustment
Vestibulo-ocular reflex

influenced: anterior corticospinal tract, reticulospinal tract, vestibulospinal/tectospinal tract, and MLF

23

Symptoms of Cerebellar lesion

Ataxia
intentional tremor
abnormal rebound effect

dysmetria
dysarthria
dysdiachokinesia

vestibular effect

24

Basal ganglia and cerebellar comparison

Similarly: both do NOT initiate movement, modifies movement

Differently: basal ganglia results in a hyper or hypo kinetic movement disorder

25

Motor function of Basal ganglia

via sensorimotor loop
gating of voluntary movement
enables practiced movement acts

26

Cognitive function of Basal ganglia

via limbic and prefrontal loop
selection of various cog/executive function
Striatal neurons heavily involved in initiating implicit movements

27

4 processing loops of the Basal ganglia

motor
ocoluomotor
prefrontal
limbic

28

Motor loop of basal ganglia main function

Disinhibition regulation

feedback to the cerebral cortex for initiating/planning of movement

facilitates intended movement patterns, inhibits extraneous movement patterns

29

Basal ganglia input

input: nearly all of the cortex with ENORMOUS convergence

terminates on: basal ganglia UMN and superior colliculus

30

Caudate receives from ___

premotor cortex
frontal eye field
limbic system
all other supplemental motor areas and other cortical associations