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Flashcards in Cerebellum Deck (24):
1

Inability to maintain proper balance resulting from cerebellar lesion

Results mainly from disruption of input from the vestibular system

disequilibrium

2

Decreased muscle tone and difficulty in maintaining posture resulting from cerebellar lesion

Results from disruption of spinocerebellar inputs

hypotonia

3

Lack of coordination of muscles that usually work together resulting from cerebellar lesion

Results from damage to the pathways from higher levels (cortico-ponto-cerebellar) or from lower levels (spinocerebellar)

asynergia

4

lack of coordination of voluntary movements resulting from cerebellar lesion

ataxia

5

Tremor most apparent during a planned movement just before the patient reaches the target resulting from cerebellar lesion

intention tremor

6

Patient tends to overshoot or undershoot reaching for a target resulting from cerebellar lesion

dysmetria

7

Mainly contains fibers entering the cerebellum from spinal cord and brainstem

Contains outputs to the medulla oblongata, vestibular nuclei and reticular formation

Attaches cerebellum to the medulla oblongata

inferior cerebellar peduncle

8

Only contains fibers entering the cerebellum from pons

Attaches the cerebellum to the pons

middle cerebellar peduncle

9

Mainly contains cerebellar outputs going to the red nucleus and VA/VL thalamus

Exception – input from spinal cord (ventral spinocerebellar tract)

Attaches cerebellum to the midbrain

superior cerebellar peduncle

10

cerebellar input
Originates from nucleus Dorsalis of Clark (C8-L2)
Runs on the ipsilateral side of the spinal cord and brainstem
Enters the cerebellum by via the inferior cerebellar peduncle
Axons synapse mainly in the anterior lobe of the cerebellum
Conveys information regarding muscle tone for the lower extremity

dorsal spinocerebellar tract

11

cerebellar input
Originates from posterior horn neurons in the spinal cord at all cord levels
Axons cross in anterior commissure of the spinal cord
Enters cerebellum in the superior cerebellar peduncle
Axons synapse mainly in the anterior lobe of the cerebellum
Conveys information about whole muscle movement

ventral spinocerebellar tract

12

cerebellar input
First order neuron (DRG cells) axons ascend in the dorsal funiculus to synapse in the lateral cuneate nucleus of the medulla oblongata (lateral to the nucleus cuneatus)
Axons of neurons in the lateral cuneate nucleus form the cuneocerebellar tract which enters the cerebellum in the inferior cerebellar peduncle and projects to the anterior lobe
Conveys information regarding muscle tone for the upper extremity

cuneocerebellar tract

13

cerebellar input
Axons cross in the medulla oblongata and enter the cerebellum in the inferior cerebellar peduncle
Axons project to the entire cerebellar cortex

inferior olivary nucleus

14

cerebellar input
Axons enter the cerebellum in the inferior cerebellar peduncle
Axons project mainly to the anterior lobe

reticular formation

15

cerebellar input
Axons enter the cerebellum in the inferior cerebellar peduncle
Axons project mainly to the flocculonodular lobe

vestibular nuclei axons and vestibular ganglion cell axons

16

cerebellar input
Axons from cerebral cortex synapse in the pontine grey nuclei
Axons of the pontine grey nuclei form pontocerebellar axons which cross in the pons to enter the cerebellum in the middle cerebellar peduncle
Motor areas of cerebral cortex project to cerebellum via pons

cerebral cortex does not connect directly to cerebellum but relays through pons

17

superficial layer of cerebellar cortex
located under the pia mater, contains mainly large bundles of unmyelinated axons packed together (parallel fibers) and dendrites of Purkinje cells

molecular layer

18

intermediate layer of cerebellar cortex
single layer of Purkinje cell bodies
Axons of Purkinje cells leave the cerebellar cortex and synapse with neurons in deep cerebellar nuclei
Purkinje cells are all inhibitory and are the only neurons of cerebellar cortex whose axons leave the cerebellar cortex
All others neurons in cerebellar cortex are interneurons

Purkinje cell layer

19

deep layer of cerebellar cortex
granule cells whose axons form the parallel fibers running in the molecular layer and synapsing on Purkinje cell dendrites, parallel fibers are excitatory

granular layer

20

originate from neurons in the spinal cord, reticular formation, vestibular nuclei, potine grey, and vestibular ganglion cells

Synapse mainly with granule cells
Enter the cerebellar cortex and send collateral axon branches to the deep cerebellar nuclei neurons where they synapse

excitatory fibers

mossy fibers

21

originate from neurons in the inferior olive and synapse mainly on dendrites of the Purkinje cells in the molecular layer

Enter the cerebellar cortex and send collateral axon branches to synapse on neurons in the deep cerebellar nuclei

excitatory fibers

climbing fibers

22

deep cerebellar nucleus
lies close to midline
receives input from Purkinje cells in the vermis, vestibular nuclei, and vestibular ganglion cells
outputs mainly go to vestibular nuclei and reticular formation
concerned with regulating extensor muscle tone and adjusting posture

fastigial nucleus

23

deep cerebellar nucleus
Several small groups of neurons found lateral to the fastigial nucleus
Receives input from Purkinje cells in the intermediate zone
Output goes to the red nucleus and VA/VL thalamus
Concerned with regulating flexor muscle tone and limb movements

globose nucleus and emboliform nucleus (interposed nucleus)

24

Largest and most laterally places deep cerebellar nuclei
Receives input from Purkinje cells in the lateral cerebellar hemispheres
Output foes to red nucleus and VA/VL thalamus
Concerned with coordinating somatic motor activity by influencing motor regions of cerebral cortex
Coordinates finger movements and skilled movements

dentate nucleus