#1 Cerebellum

Question 1

What are the functions of the cerebellum?

Answer 1

• Regulates equilibrium
• Controls muscle tone and posture
• Provides motor coordination for voluntary movements
• In the near future, such as pitcher getting ready to pitch.
• And During execution, like adjusting ongoing motor activity. like when you thought there was another step but there wasn’t…..you can thank your cerebellum for keeping you from falling.

Question 2

_____ divides the body of the cerebellum into Ant. and Post. lobes.

Answer 2

Primary fissure

Question 3

______ seperates flocculonodular lobe from body of cerebellum.

Answer 3

Posterolateral Fissure

Question 4

The cerebellum is attached to the brain by _______.

Answer 4

3 Cerebellar peduncles:

• ICP
• MCP
• SCP

Question 5

Describe the inputs and function of the ICP…

Answer 5

Inputs from the spinal cord.

Function - monitors muscle and limb movement.
*Juxtarestiform body = interconnect vestibular nuclei and cerebellum.

Question 6

Describe the input and function of the MCP…

Answer 6

Input = afferents from central lateral basis pontis.
Function =  relays motor signal from cerebral cortex to cerebellum.

*MCP is largest

Question 7

Describe function of SCP….

Answer 7

Efferents to red nucleus and thalamus…

Question 8

What are the 3 cerebellar deep Nuclei?

Answer 8

1. Dentate (biggest) = contributes most fibers in SCP.
2. Interposed nucleus
   - Emboliform
   - Globose
3. Fastigal (smallest & most ancient) *looks like Mickey mouse ears.

Question 9

What are the 4 basic steps of Cerebellar circuitry?

Answer 9

1. Inputs arrive at ICP & MCP (Mostly @ MCP) and then project to cortex.
2. Cortex does its thing
3. Cortex sends info to deep nuclei of cerebellum.
4. Deep nuclei send projection (Mostly SCP) to other parts of the brain.

Question 10

Describe the 3 layers of the cerebellar cortex top to bottom.

Answer 10

1. Molecular layer (top) = contains purkinje cell dendrites & granule neuron axons.
2. Purkinje cell layers (middle) = single cell layer * only axons to leave cortex!
3. Granule layer (bottom) = 10 to the 11th

Question 11

What are the 3 fibers of cerebellar cortical circuitry?

Answer 11

1. climbing fibers
2. Mossy fibers
3. Parallel fibers

Question 12

What are Climbing fibers?

Answer 12

Axon from contralateral inferior olivary nucleus that is a major cortical input

Question 13

What are Mossy fibers?

Answer 13

Input from brainstem, vestibular system & spinal cord that is a major cortical input.

Question 14

What are parallel fibers?

Answer 14

Axon from granule neuron/cell (does not leave cortex)

Question 15

Where does Inferior olivary nuclei get info from?

Answer 15

Spinal cord, red nucleus, cerebral cortex.

Question 16

Where do climbing fibers go specifically?

Answer 16

From ION, ascend to contralateral ICP and enter cerebellum

Question 17

What is the basic function of climbing fibers?

Answer 17

Regulate parking cell firing by synapsing on them.

Question 18

In the _____ layer there are interneurons know as _____, ______ & ______.

Answer 18

Molecular layer

Stellate, basket & Golgi cells

Question 19

Where do Mossy fibers go specifically?

Answer 19

Send collaterals to deep nuclei before axons enter cortex

*Purkinje fibers end in deep nuclei

Question 20

Deep nuclei have 2 neuronal populations, what are they?

Answer 20

• Source od mossy fibers to cortex

- Projection neurons whose axons leave cerebellum.

Question 21

What are the 3 functional zones of the cerebellum?

Answer 21

Vestibulocerebelllum (inner) = flocculonodular lobe & Vermis (Fastigial nucleus)

Spinocerebellum (middle) = paravermal area (interposed nucleus)

Pontocerebellum (Outer) = lateral hemisphere projects to dentate nucleus.

Question 22

What is the input, output and function of the Vertibulocerebellum zone?

Answer 22

Input = vestibular end organ and vestibular nuclei
Output = Fastigial nucleus & Vestibualr nuclei

Function = control eye movements in response to head movements & balance.

Question 23

What is the input, output and function of the Spinocerebellum zone?

Answer 23

Input = Spinal cord (spinocerebellar tracts) and brainstem (trigeminal afferents)
Output = Interposed nucleus, red nucleus and VA/VL of thalamus.

Function = Coordination of truck and limb movements.

Question 24

What is the input, output and function of the Pontocerebellum zone?

Answer 24

Input = motor cortex, basilar pons, MCP
Output = Dentate nucleus, red nucleus & VA/VL of thalamus

Function = Planning the timing of movements especially those of the upper extremities. Also coordination of speech.

Question 25

what is the function of the lateral cerebellar zone?

Answer 25

planning learned, skillful movements that become more precise and rapid with practice.

Question 26

Injury to Lateral cerebellar zone can cause what?

Answer 26

Involvement of arm and speech.

• intention tremor
• dysdisadochokinesa = rapid alternating movements.
• dysmetria = finger to nose test
• Dysarthria = scanning or explosive speech.

Question 27

What is the function of the medial hemisphere of cerebellum

Answer 27

adjusting limb movements.

Question 28

What is the function of the Vermis of the cerebellum?

Answer 28

Postural adjustments

Question 29

Damage to the vermis can result in what?

Answer 29

• Truncal ataxia
• disturbances in balance while seated
• standing and gait ataxia

Question 30

What is the function of the Flocculus & Vermis?

Answer 30

Eye movements

Question 31

Damage to the Flocculus & vermis can cause what?

Answer 31

Nystagmus (eyes back and forth)

Question 32

What is the major output from Cerebellar nuclei?

Answer 32

SCP

Question 33

What are the major inputs to the Cerebellar cortex.

Answer 33

Vermis = Fastigial
Medial hemi. = interposed
Lateral Hemi = dentate

Question 34

One side of cerebellum affects _______ limbs.

Answer 34

Ipsilateral

Question 35

One Cerebral hemisphere controls ________ muscles.

Answer 35

Contralateral

Question 36

Cerebellum projects to _______ thalamus.

Answer 36

Contralateral