Cerebellum

Question 1

general purpose of cerebellum

Answer 1

modulate movement and may be involved w/ non motor functions such as learning and memory

Question 2

what separates the pons/medulla from the cerebellum

Answer 2

the 4th ventricle

Question 3

cerebellar peduncles

Answer 3

superior- output to midbrain

middle- input from pons (pontine nucleus)

inferior- input and output to medulla (vestibular nerve/nucleus)

Question 4

describe the tract of the superior peduncle

Answer 4

they are visible posteriorly disappearing into the midbrain at the level of the inferior colliculus. They decussate shortly thereafter and terminate in the thalamus (ventral lateral or ventral anterior) or red nucleus

Question 5

vermis

Answer 5

midline between two cerebral hemispheres

Question 6

folia

Answer 6

transverse folds on the surface of the cerebellum

Question 7

arbor vitae

Answer 7

white matter tree like appearance in the sagittal view of the cerebellum

Question 8

cerebellar primary fissure

Answer 8

separates the anterior from posterior lobe

Question 9

posterolateral fissure

Answer 9

divides posterior and flocculonodular lobes

Question 10

tonsil

Answer 10

lies just superior to foramen magnum

Question 11

vestibulocerebellum

Answer 11

flocculonodular
archicerebellum

receives information from the vestibular system and regulates balance and reflex eye movements

Question 12

spinocerebellum

Answer 12

midline cerebellum immediately lateral vermis

receives info from spinal cord and adjusts ongoing movements and controls muscle tone

Question 13

cerebrocerebellum

Answer 13

pontocerebellum or neocerebellum

lateral portions of the hemispheres

receives info from contralateral cortex via pontine nuclei

planning and initiation of skilled movements and in learning of new movements

Question 14

deep cerebellar nuclei

Answer 14

fastigial- inner most
interposed nuclei
dentate- outer most nuceli- largest and travels through superior peduncle

receive output from cerebellar cortex and give rise to main cerebellar outputs

Question 15

describe the gray matter of the cerebellar cortex

Answer 15

3 layers- molecular layer, purkinji layer, and granule cell layer

5 cell types total, all except granule cells GABA

purkinji cells- only output from cerebellar cortex, axons terminating in deep cerebellar nuclei. dendrites are in the molecular layer

granule cells- from granule layer, send axon into molecular layers, where they travel sideways and synapse with many purkinje dendrites. called parallel fibers

golgi, basket, and stellate cells- inhibitory interneurons

Question 16

mossy fibers

Answer 16

main input from other parts of the brain comes in as mossy fibers- synapse on granule cells

results in the excitation of purkinji fibers

also directly synapse with deep cerebellar nuclei

Question 17

climbing fibers

Answer 17

extend up to purkinje fibers and wrap around it. main input is inferior olivary nucleus

also directly synapse with deep cerebellar nuclei

Question 18

output from the cerebellar cortex vs output from the deep cerebellar nuclei

Answer 18

purkinje fibers are inhibitory

deep nuclei are ecitatory

purkinje modulation of deep nuclei output is “inhibitory sculpting”

Question 19

short v long term plasticity

Answer 19

short- changes lasting a few minutes or less

long- changes lasting 30 minutes or longer

Question 20

motor learning

Answer 20

occurs between parallel fibers and purkinji fibers. glutaminergic synapse acting on AMPA receptors and metabotropic glutamate

climbing neurons activate purkinji fibers using aspartate when motor performance does not match expectations. this causes an increase in Ca, eventually activating PKC

PKC phosphorylates AMPA receptors used in the parallel fibers. phosphorylated AMPA receptors become less effective and are internalized

if a parallel fiber is also activated at the same time, it’s connection to purkinji fibers are subsequently weakened

Question 21

flocculonodular lobe

Answer 21

corresponds with vestibulocerebellum

receives info from vestibular system via inferior peduncle and regulates balance and reflex eye movements. controls VOR and spinal muscle tone

output is ipsilateral back to vestibular nuclei via inferior pedcunles via purkinji fiber axons

Question 22

spinocerebellum

Answer 22

receives info from spinal cord, adjusts movements and controls muscle tone

also receives proprioception from dorsal spinocerebellar (lower limb) and cuneocerebellar pathway (upper limb)

primary input from spinal cord via inferior peduncle

output from vermis- ipsilateral fasitigal nucleus- project to brainstem (vestibular nuclei or reticular formation) bilaterally via inferior peduncle. controls axial muscles via vestibulo and reticulospinal tracts

output from intermediate- ipsilateral interposed nuclei- project contralaterally to red nucleus and motor cortex via VL nucleus of thalamus. controls limb muscles via rubrospinal and laterl corticospinal tracts. travels thru superior peduncle

Question 23

vermis vs intermediate zone input

Answer 23

vermis- receives info from trunk muscles

intermediate- receives info from limb muscles

Question 24

double crossing

Answer 24

output from intermediate zone decussates in superior peduncle, and then again in the rubrospinal or lateral corticospinal tract

Question 25

cerebrocerebellum

Answer 25

receives info from cerebral cortex via pontine nuclei and corticopontine tract. enter thru middle cerebellar peduncle

planning and initiation of skilled movements- voluntary motor sequences

purkinji fibers- dentate nucleus- cerebellar peduncle- VL of thalamus and red nucleus

dentathalamic fibers- fibers that go to thalamus and then to motor cortex

dentatorubal fibers- go to red nucleus and then ipsilaterla inferior olive