Hirsch - Cerebellum

Question 1

function of cerebellum

Answer 1

compare motor plans with physical execution

make adjustments to keep movements coordinated, fluid, and on target

also involved in motor learning

Question 2

cerebellar disorder

1. ataxia

Answer 2

reeling, wide based gait

Question 3

cerebellar disorder

2. decomposition of movement (general)

Answer 3

inability to correctly sequence fine, coordinated acts

Question 4

cerebellar disorder 2.1. dysarthria

Answer 4

inability to articulate words correctly with slurring and inappropriate phrasing

Question 5

cerebellar disorder 2.2. dysdiadochokinesia

Answer 5

inability to perform rapid alternating movements

Question 6

cerebellar disorder 2.3. dysmetria

Answer 6

inability to control range of movement (hypo or hypermetria)

Question 7

cerebellar disorder 2.4. hypotonia

Answer 7

decreased muscle tone

Question 8

cerebellar disorders 2.5. nystagmus

Answer 8

involuntary, rapid oscillation of the eyeballs in a horizontal, vertical or rotary direction with the fast component maximal toward the side of the cerebellar lesion

Question 9

cerebellar disorders 2.6. tremor

Answer 9

rhythmic, alternating, oscillatory movement of a limb as it approaches a target (intention tremor) or of proximal musculature when fixed posture or weight bearing is attempted (postural tremor)

Question 10

arbor vitae

Answer 10

whitematter of cerebellum

Question 11

functional divisions of cerebellar cortex

Answer 11

cerebrocerebellum (neocerebellum)

spinocerebellum (paleocerebellum)

vestibulocerebellum

Question 12

cerebrocerebellum

Answer 12

lateral

phylogenetically new

receive input from contralateral cerebral cortex

regulate complex sequence of movement including speech

Question 13

spinocerebellum

Answer 13

paramedian and median (vermis zone)

phylogenetically older than neocerebellum

receive input from spinal cord

somatotopic organization

* paramedian: regulate distal muscles

* median: regulate proximal muscle and some eye movements

Question 14

vestibulocerebellum

Answer 14

caudal and inferior lobes

phylogenetically ancient

receives input from vestibular nuclei (in brainstem)

regulate posture and balance including eye movements

Question 15

deep cerebellar nuclei

Answer 15

dentate

interposed

fastigial

Question 16

dentate nucleus

Answer 16

input from cerebrocerebellar zone

projects to:

1. contralateral premotor cortex
2. association cortices of frontal lobe involved in planning movement

Question 17

Interposed nucleous

Answer 17

globose nucleus + emboliform nucleus

input from spinocerebellar zone

projects to:

contralateral motor cortex (aid executing movement)

Question 18

Fastigial nucleus

Answer 18

input from spinocerebellar zone

projects to:

upper motor neurons (in ipsilateral brainstem)

to aid executing movement

Question 19

vestibulocerebellum

Answer 19

project to vestibular nuclei

NOT to cerebellar nuclei

Question 20

cerebellar peduncles

*afferent connection arrives

*efferent connection exits

Answer 20

fiber bundles carrying inputs and outputs

1. superior (brachium conjuntivum)
2. middle(info to cerebellum)
3. Inferior (restiform body

Question 21

superior peduncles - cerebellar

Answer 21

efferent pathway exiting from deep cerebellar nuclei

Question 22

middle peduncles

Answer 22

afferent pathway carrying information from the cortex via the pons

Question 23

inferior peduncle

Answer 23

mixed;

afferent come from brainstem and spinal cord

efferent exit from vestibulocerebellum

Question 24

know picture in (7/16) for structures associated with cerebellum

Answer 24

medial premotor cortex and primary motor cortex

VA/VL complex of thalamus

cerebellar cortex

deep cerebellar nuclei

pontine nuclei

vestibular nuclei

inferior olive

external cuneate nucleus

dorsal nucleus of Clarke

Question 25

Inputs to cerebellum

Answer 25

1. from cerebral (frontal/parietal) cortex:

project to pontine nuclei (ipsilateral)

controls contralateral side of the body

2. cerebellar hemisphere:

receive ascending input from ipsilateral side of body

control movements on the same side of the body

** pathway from cerebral cortex to cerebellum cross at middle cerebellar peduncle

Question 26

Ascending outputs of the cerebellum

Answer 26

cerebrocerebellum -> premotor cortex via dentate (motor planning);

part of it spreads to red nucleus parvocellular

spinocerebellum -> motor cortex via interposed nuclei (motor execution)

Question 27

descending outputs of the cerebellum

Answer 27

spinocerebellum -> brainstem via fastigial nucleus (motor execution)

vestibullocerebellum -> project directly to vestinular nuclei (motor adjustment, balance)

Question 28

Cytoarchitecture of the cerebellum

three layers of cerebellar cortex from out to in

Answer 28

1. molecular layer (ML) - dendrites of purkinje cells and axons of granule cells (parallel fibers)
2. Purkinje cell layer (PL) - purkinje cells and basket cells
3. granule cell layer (GL) - granule cells have “claws”

Question 29

cerebellar circuits

climbing fibers

mossy fibers

Answer 29

climbing fibers - comes from inferior olive

mossy fiber - comes from pontine nuclei

Question 30

climbing fiber and purkinje cell

Answer 30

purkinje cell receive input from a single clibing fiber (from inferior olive) (ONE)

fires “complex spike” in response to input from a clibing fiber

Question 31

inferior olive

Answer 31

makes single climbing fiber to purkinje cells

receives input from cerebral cortex, spinal cord, and “red nucleus”

Question 32

mossy fiber and purkinje cell

Answer 32

come from pontine nuclei

synapse with granule cells

purkinje cell receives hundreds of thousands of inputs from parallel fibers (MANY)

purkinje cells fire “simple” spikes in response to input from parallel fibers

Question 33

pontine nuclei

Answer 33

make mossy fibers to granulle cell (parallel fibers)

relay input from cerebral cortex, spinal cord and “vestibular nuclei”

Question 34

motor learning: cerebellum can learn to compensate changes in the status quo

Answer 34

ex. normal vestibulo-ocular reflex (VOR) vs. VOR out of register using minifying glasses

—> VOR gain reset by moving eyes in smaller distance to compensate

movement adjusts to the vision

Question 35

cerebellar loops

Answer 35

1. direct loop (deep excitatory)
2. cortical inhibitory loop
3. climbing fiber loop

Question 36

direct loop; deep excitatory

Answer 36

from mossy fibers

(afferent information)

to deep cerebellar nuclei

“motor system - a reflex pathway”

Question 37

cortical inhibitory loop

Answer 37

from mossy fibers

via parallel fibers

to granule cells

to purkinje cells

to ddep cerebellar nuclei and motor system

“to fine-tune reflexes”

Question 38

climbing fiber loop

Answer 38

detect errors

correct them over longterm

“motor learning loop”

Question 39

motor learning

Answer 39

climbing fiber loop & complex spike

important

Question 40

climbing fibers derive from ______

mossy fibers come from ______

Answer 40

climbing fibers derive from inferior olive

mossy fiber come from pontine nuclei

Question 41

know how to draw (16/16)

Answer 41

1. planning and programming

(sensory association cortex, basal ganglia, lateral hemisphere of cerebrocerebellum ===>premotor cortical area)

2. movement

( ==> motor cortex, vermis and intermmediate hemisphere of spinocerebellum)

3. feedback signals

(vermis and intermediate hemisphere of spinocerebellum)