Cerebellum

Question 1

where is cerebellum located

Answer 1

posterior cranial fossa, below tentorium cerebelli

Question 2

functions of cerebellum

Answer 2

1. regulate equilibrium
2. control mm tone and posture
3. motor coordination for voluntary movements

Question 3

cerebellum primary function

Answer 3

motor adaptation (modification in response to environment)

Question 4

structure of cerebellum

Answer 4

• folia = gyri, fissures = sulci
• nodulus of vermis (vestibulocerebellum) in center
• paravermal area on either side of vermis

Question 5

primary fissure

Answer 5

separates ant and post lobes

Question 6

where do ant and post lobes each receive input from

Answer 6

ant: from SC
post: from pons

Question 7

posterolateral fissure

Answer 7

separates nodulus from rest of vermis

Question 8

what are the 3 deep cerebellar nuclei, what do they do

Answer 8

1. dentate nucleus
2. interposed nucleus
3. fastigal nucleus

*have axons that leave the cerebellum

Question 9

dentate nucleus

Answer 9

contributes most fibers in SCP, lateral hemisphere projects here

Question 10

interposed nuc

Answer 10

made of 1. emboliform and 2. globose nuc, medial hemisphere projects here

Question 11

fastigal nucleus

Answer 11

vermis projects here

Question 12

inf cerebellar peduncle

Answer 12

1. restiform body: input from SC and BS, monitors mm and limb moves
2. juxtarestiform body: connects vestibular nuc and cerebellum

Question 13

middle cerebellar peduncle

Answer 13

(brachium pontis)

largest, lateral to pons, afferents from contralat basis pontis, relays motor signals from cerebral cortex

Question 14

what are the two largest paths into the cerebellum?

Answer 14

inf and mid cerebellar peduncles

Question 15

superior cerebellar peduncle

Answer 15

(brachium conjunctivum)
mostly efferent fibers to red nuc and thalamus
major cerebellar outflow path

Question 16

climbing fibers

Answer 16

• originate in inferiior olivary nucleus in rostral medulla

- travel in inf cerebellar peduncle

Question 17

mossy fibers

Answer 17

• provide info from SC and BS

- travel in inf and mid cerebellar peduncle, synapse in granular layer

Question 18

path of climbing and mossy fibers

Answer 18

go to purkinje cell layer (piriform) and synapse in molecular layer, go to deep cerebellar nuclei, exit via sup OR inf cerebellar pedunces

sup: to red nuc and thalamus
inf: to vestibular nuclei

Question 19

cerebellar afferents

Answer 19

1. SCTs (ant-sup ped, pot- inf ped, cuneocerebellar- inf ped)
2. trigeminal n (all 3 peduncles)
3. tectocerebellar tract (ipsilat colliculi)
4. vestibulocerebellar tract (ipsilat vestib nuc)
5. pontocerebellar tract (mid ped)
6. olivocerebellar tract (inf ped)
7. reticulocerebellar (inf ped)

Question 20

what facilitates transmissions in climbing and mossy fibers

Answer 20

serotonergic and noradrenergic synapses

Question 21

origin, representation, input and crossing of ASCT

Answer 21

origin: spinal border cells (T12-L5)
rep: trunk/leg
input: mechanoreceptors and move related interneurons
cross: at midline, again in cerebellum

Question 22

origin, representation, input and crossing of PSCT

Answer 22

origin: clarkes nuc (T1-L2/3
rep: trunk/leg
input: mechanoreceptors in mm, joints, and skin
crossing: NO

Question 23

origin, representation, input and crossing of CCT

Answer 23

origin: lat cuneate nuc in medulla
rep: trunk/arm
input: mechanoreceptors in mm, joints, and skin
crossing: NO

Question 24

what is inf olivary nuc involved with

Answer 24

motor learning and the acquisition of new motor skills

Question 25

how/where does sensorimotor cortex in olivocerebellar tract project where does it get info from

Answer 25

via corticospinal collaterals onto ipsilateral olive info from SC, red nuc, and cerebral cortex

Question 26

purkinje cells at rest and with training

Answer 26

at rest: groups of olivary neurons cause complex spikes | w/ training: simple spikes

Question 27

red nucleus (afferent tract) in/outputs

Answer 27

in rostral midbrain - inputs: collaterals from 1. cerebral cortex descending to olive 2. cerebellar output fibers ascending to thalamus - outputs: inhibitory signal to ipsilateral olivary nucleus

Question 28

layers of cerebellar cortex

Answer 28

1. molecular layer (top): 2. purkinje cell layer: only axons to leave cortex 3. granular layer: densely cellular

Question 29

cortical afferents vs efferents

Answer 29

afferents (excitatory): glutaminergic | efferents (inhibitory) GABAnergic

Question 30

where do purkinje cell axons end?

Answer 30

in deep nucleus

Question 31

neuronal populations of deep nucleus

Answer 31

1. source of mossy fibers into cortex | 2. projection neurons w/ axons leaving cerebellum

Question 32

functional zones

Answer 32

fractionated somatotopy in ant and post lobes *axial mm by midline, limbs lat 1. vestibulocerebellum 2. spinocerebellum 3. pontocerebellum/neocerebellum

Question 33

vestibulocerebellum (afferents)

Answer 33

- in flocculonodular lobe and part of vermis - input: from vestibular labyrinth and nuc - output: to fastigal nuc - fnctn: control eye movements in response to head moves, balance

Question 34

spinocerebellum (afferents)

Answer 34

- in paravermal area, part of vermis - input: from spinocerebellar tracts, BS - output: interposed nuc (red nuc) - fnctn: posture and gait, coordination of trunk and limb moves

Question 35

pontocerebellum/neocerebellum (afferents)

Answer 35

- in lat cerebellar hemi - inputs: from motor cortex (basilar pons), MCP - outputs: dentate nuc (red nuc, VA/VL of thalamus) - fnctn: planning timing of movements (UL), coordination of speech