Cerebellum

Question 1

what do lesions to the cerebellum do

Answer 1

cuase decomposition of movements into their indiv components which then become uncoordinated (ataxia)

• motor deficts but not paralysis bc cerebellum modulates motor activity
• NO SENSORY DEFICITS

Question 2

what lobes do the primary fissure separate

what lobes do the posterolateral fissure separate

Answer 2

anterior lobe and post lobe

posterior lobe and flocculonodular lobe

Question 3

whats the only lateral cerebellar peduncle?

Answer 3

MCP

comes off the lateral pons

Question 4

why can you not see the nodules from the ventral aspect but you can see the flocculus

Answer 4

bc the nodulus is off the vermis and it’s midline and it is INside
-nodulus would be the very last little nub of vermis sitting INSDIE the 4th vetnricle

Question 5

what is it called when the tonsils hang below the level of the foramen magnum

Answer 5

arnold chiari malformation

Question 6

what are folia

Answer 6

the tiny folds (gyri) over the cerebellar cortex

Question 7

where is the deep cerebellar nuclei embedded in

Answer 7

embedded deep w/in the white matter

-but is gray matter “nuclei”

Question 8

is the medullary portion gray or white matter

Answer 8

white matter

Question 9

what do each of the 3 layers of the cerebellar cortex contain

Answer 9

1. molecular layer: most external w/ axons (of granule cells) and dendrites (of purkinje cells)
   2: purkinje layer: indiv cell bodies of purkinje cells lined up in a row
2. granule layer: most internal layer of the cerebellar cortex

Question 10

are purkinje cells exhibitory or inhibitory? what neurotransmitter do they use

Answer 10

inhibitory

GABA

Question 11

what nt do granule cells use

Answer 11

glutamate

Question 12

how do inputs enter the cerebellum?

Answer 12

as mossy fibers or climbing fibers

Question 13

incoming mossy fibers provide _____ input directly onto _____Cells

Answer 13

excitary input directly onto granule cells in the granule layer

Question 14

wehre do climbing fibers come from and wehre do they enter

-what kind of contact do these make on purkinje cells

Answer 14

come from the inf olive and enter the cerebellum via the inf cerebellar peduncle
-each climbing fiber makes a massive, strong excitatory contact onto one or a small number of purkinje cells

Question 15

purkinje cells send their axons down, out of the cerebellar cortex to synapse on what

Answer 15

1. a deep cerebellar nucleus (DCN) embedded deep w.in the cerebellar white matter or
2. a vestibular nucleus in the brainstem

Question 16

what does a strong activation of a purkinje cell cause

Answer 16

a decreased activation of its target

Question 17

why is the output of the cerebellar cortex inhibitory

Answer 17

bc the only ecll leaving the cerebellar cortex is the purkinje cell, which is inhibitory

Question 18

what is the sole efferent neuron of the cerebellar cortex

Answer 18

purkinje cell

Question 19

wht are the 4 pairs of DCN -deep cerebellar nuclei

Answer 19

medial to lateral: 
fastigial
globose
emboliform
dentate

Question 20

wehre do the interposed and fastigial nuclei receive inputs from

Answer 20

vermis and paravermis areas (spinocerebellum)

Question 21

wehre does the dentate nuclei receive input from

Answer 21

cerebellar hemispheres (cerebrocerebellum)

Question 22

in most cases, the fibers of the DCN leave the cerebellum through..

Answer 22

the superior cerebellar peduncle (SCP)

Question 23

what are the 3 functional areas that the cerebellum is divided into

Answer 23

1. spinocerebellum=vermis and intermediate zone
2. cerebrocerebellum=hemispheres
3. vestibulocerebellum=flocculonodular complex

Question 24

what is the spinocerebellum’s function

Answer 24

• important for control of body muscularature for gait and posture (output)
• coordinate w/ spinal cord (input)

Question 25

what is cerebrocerebellum’s function

Answer 25

• importnat for planning movements (output)

- coordinates w/ cerebral cortex (input)

Question 26

what is the vestibulo-cerebellum’s function

Answer 26

• importnat for balance, posture, and eye movements (output)

- coordinates w/ inner ear (input)

Question 27

the cerebellum has _____ impact on motor activity by impacting the ______;

Answer 27

indirect
UMNs
there is no direct impact on the LMNs

Question 28

what does dysfucntion of the spinocerebellum do

Answer 28

vermal outputs: results in gait and truncal ataxia

paravermal: appendicular ataxia

Question 29

what are the inputs to the spinocerebellum via

Answer 29

via the dorsal spinocerebellar tract and the cuneocerebellar tract

Question 30

where do mossy fibers synapse at

Answer 30

granuel cells

Question 31

what do cerebellar lesions cause

Answer 31

ipsi clinical deficits

Question 32

proprioceptive input info from the right arm/leg =>____ spinocerebellum => ____ thalamus => ____ motor cortex ==> ____ sided body msucles

Answer 32

right spinocerebellum
left thalamuc
left motor cortex
right sided body muscles

Question 33

what does damage to the spinocerebellum cause

Answer 33

ataxia of stance and gait

decreased muscle tone (hypotonia)

Question 34

where is the cerebrocerebellum located

Answer 34

lateral hemispheres

Question 35

what are the inputs and outputs of the cerebrocerebellum

Answer 35

receives input from the cerebral cortex (motor cortex) and sends outputs back to the cerebral cortex via VA/L thalamus

Question 36

what is the cerebrocerebellum mostly concerned w/

Answer 36

coordinating distal musculature

ex reaching and grasping

Question 37

what does a lesion at the cerebrocerebellum give

Answer 37

ataxia

Question 38

the pontocerebellars enter the cerebellum via the MCP as ________ and synpase on the granule cells

Answer 38

mossy fibers and synpase on the granule cells of the cerebrocerebellar cortex

Question 39

where will the fibers of the cerebrocerebellum go

Answer 39

many of these fibers will rise to VA/VL thalamus (which will then project to cortex)
1/3 will rise to the red nucleus

Question 40

what is the path of the cerebrocerebellum fibers

Answer 40

1. pontocerebellars enter the cerebellum via the MCP as mossy fibers and synpase on the granule cells of the cerebrocerebellar cortex
2. granuel cell axons go up the molecular layer
3. bifurcate in a T shaped fashion and synapse on Purkinje dendritic tree
4. purkinje cell then sends its efferent inhibitory axon down to synapse on dentate nucleus
5. fibers exit cerebellum and re-enter the brainstem through a cerebellar peduncle on ramp (SCP)
6. fibers of SCP decussate at lvl of caudal midbrain
7. fibers rise to VA/VL thalamus but 1/3 go to red nucleus

Question 41

what happens when there is a lesion to the cerebrocerebellum

Answer 41

loss of coordinated muscle activity

• ataxia
• dysmetria
• scanning speech
• dysdiadochokinesia
• nystagmus
• rebound phenomenon

Question 42

where can inputs to the vestibulocerebellum come from

Answer 42

1. from the vestibular labyrinth (hair cells in the otolish organs-utricle, saccule, or semicircular canals)
2. from vestibular nuclei (located in the lateral recess of the floor of the 4th ventricle)

Question 43

if you are a purkinje cell are you’re in the flocculonodular lobe (vestibulocerebellum) where do you synpase on

Answer 43

vestibular nuclei (not in the cerebellum but in the brainstem)

• act as surrogates for the DCN
• vest nuclei receive info directly from purkinje cells

Question 44

what does the MLF connect

Answer 44

connected all the EOM nuclei (3, 4, 6)

Question 45

clinically, what happens whn there is a lesion to the cerebellum midline?
what happens when there is damage to the latral hemispheres?

Answer 45

midline ataxia from lesions to cerebellum midline

appendicular ataxia from damage to the lateral hems

Question 46

what happens in midline ataxia

Answer 46

lead to functinal deficit w/in the vestibulocerebellum or spinocerebellum
-instability of people as they sit, stand, walk

Question 47

what are the hallmarks of hemispheric cerebellar disease

Answer 47

• ipsi, appendicular
• ataxia of movements of extremities: dysmetria (abnormalility of hitting their target), intention tremor, dysdiadochokinesia (incoordination of rapid alternating movemtn)
• ataxia of speech