cerebellum

Question 1

Inferior peduncle inputs

Answer 1

most of the ascending info from the spinal cord (dorsal spinocerebellar tract originating in clarke’s nucleus brings info from below T6). from upper limb to the cerebellum via cuneocerebellar tract (external arcuate nucleus).
also axons from inferior olivary nucleus: climbing fibers to the Purkinje cells.

Question 2

superior cerebellar peduncle inputs

Answer 2

ventral spinocerebellar tract. feedback and copy info about which muscles are being activated.

Question 3

middle peduncle inputs

Answer 3

descending info from the cerebral cortex.
corticofugal axons run with corticospinal tract until the pons. then, they synapse on pontine nuclear neruons. axons cross and enter the cerebellm via middle peduncle.

Question 4

mossy fibers

Answer 4

most incoming axons end in sprays called mossy fibers. they are in the internal granular layer.

Question 5

parallel fibers

Answer 5

axons from the internal granular layer of the cerebellar cortex. pass through the purkinje layer to the molecular layer. bifurcate in the molecular layer and send collaterals in either direction. synapse on the dendrites of the Purkinje cells.

Question 6

complex vs. simple spikes. role of purkinje fibers

Answer 6

complex spikes: APs of cerebellar purkinje cells caused by input from the climbing fibers of the inferior olive. discharge especially when a motor error is made. these discharges can change simple spike pattern: the cerebellum is plastic and can learn to be more coordinated.
simple spikes: much more frequent.
purkinje fibers only fibers that leve the cerebellar cortex. all gaba-ergic.

Question 7

cerebellar outputs course.

Answer 7

from the deep cerebellar nuclei (not the cerebellar cortex)
leave through the superior cerebellar peduncle
dive into the midbrain
decussate at the brachium conjuctivum
ascend through the red nucleus. many synapse. many then go to the inferior olive- which sends projections back up to the cerebellum. lesions of this loop –> palatal myoclouns.
or, go to the thalamus. synapse at the VL nucleus. go to cortical motor areas.
a very small minority of outputs go to the spinal cord or synapse on reticular formation.

Question 8

parts of the floculonodular lobe and their roles

Answer 8

nodulus (midline area): role in modulating vestibulo-ocular reflexes
flocculus: role in smooth pursuit eye movements

Question 9

2 loops connecting the motor cortex and the cerebellum and 1 extra loop.

Answer 9

motor cortex to pontine nuclei to cerebellum to thalamus VL to motor cortex
motor cortex to red nucleus to inferior olivary nucleus to cerebellu, to thalamus VL to motor cortex.
also, red nucleus to inferior olivary nucleus to red nucleus.

Question 10

what kind of motor neuron problem shows fasciluations and fibrillations

Answer 10

LMN