#1 Cerebellum Flashcards
What are the functions of the cerebellum?
- 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.
_____ divides the body of the cerebellum into Ant. and Post. lobes.
Primary fissure
______ seperates flocculonodular lobe from body of cerebellum.
Posterolateral Fissure
The cerebellum is attached to the brain by _______.
3 Cerebellar peduncles:
- ICP
- MCP
- SCP
Describe the inputs and function of the ICP…
Inputs from the spinal cord.
Function - monitors muscle and limb movement.
*Juxtarestiform body = interconnect vestibular nuclei and cerebellum.
Describe the input and function of the MCP…
Input = afferents from central lateral basis pontis. Function = relays motor signal from cerebral cortex to cerebellum.
*MCP is largest
Describe function of SCP….
Efferents to red nucleus and thalamus…
What are the 3 cerebellar deep Nuclei?
- Dentate (biggest) = contributes most fibers in SCP.
- Interposed nucleus
- Emboliform
- Globose - Fastigal (smallest & most ancient) *looks like Mickey mouse ears.
What are the 4 basic steps of Cerebellar circuitry?
- Inputs arrive at ICP & MCP (Mostly @ MCP) and then project to cortex.
- Cortex does its thing
- Cortex sends info to deep nuclei of cerebellum.
- Deep nuclei send projection (Mostly SCP) to other parts of the brain.
Describe the 3 layers of the cerebellar cortex top to bottom.
- Molecular layer (top) = contains purkinje cell dendrites & granule neuron axons.
- Purkinje cell layers (middle) = single cell layer * only axons to leave cortex!
- Granule layer (bottom) = 10 to the 11th
What are the 3 fibers of cerebellar cortical circuitry?
- climbing fibers
- Mossy fibers
- Parallel fibers
What are Climbing fibers?
Axon from contralateral inferior olivary nucleus that is a major cortical input
What are Mossy fibers?
Input from brainstem, vestibular system & spinal cord that is a major cortical input.
What are parallel fibers?
Axon from granule neuron/cell (does not leave cortex)
Where does Inferior olivary nuclei get info from?
Spinal cord, red nucleus, cerebral cortex.
Where do climbing fibers go specifically?
From ION, ascend to contralateral ICP and enter cerebellum
What is the basic function of climbing fibers?
Regulate parking cell firing by synapsing on them.
In the _____ layer there are interneurons know as _____, ______ & ______.
Molecular layer
Stellate, basket & Golgi cells
Where do Mossy fibers go specifically?
Send collaterals to deep nuclei before axons enter cortex
*Purkinje fibers end in deep nuclei
Deep nuclei have 2 neuronal populations, what are they?
- Source od mossy fibers to cortex
- Projection neurons whose axons leave cerebellum.
What are the 3 functional zones of the cerebellum?
Vestibulocerebelllum (inner) = flocculonodular lobe & Vermis (Fastigial nucleus)
Spinocerebellum (middle) = paravermal area (interposed nucleus)
Pontocerebellum (Outer) = lateral hemisphere projects to dentate nucleus.
What is the input, output and function of the Vertibulocerebellum zone?
Input = vestibular end organ and vestibular nuclei Output = Fastigial nucleus & Vestibualr nuclei
Function = control eye movements in response to head movements & balance.
What is the input, output and function of the Spinocerebellum zone?
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.
What is the input, output and function of the Pontocerebellum zone?
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.
what is the function of the lateral cerebellar zone?
planning learned, skillful movements that become more precise and rapid with practice.
Injury to Lateral cerebellar zone can cause what?
Involvement of arm and speech.
- intention tremor
- dysdisadochokinesa = rapid alternating movements.
- dysmetria = finger to nose test
- Dysarthria = scanning or explosive speech.
What is the function of the medial hemisphere of cerebellum
adjusting limb movements.
What is the function of the Vermis of the cerebellum?
Postural adjustments
Damage to the vermis can result in what?
- Truncal ataxia
- disturbances in balance while seated
- standing and gait ataxia
What is the function of the Flocculus & Vermis?
Eye movements
Damage to the Flocculus & vermis can cause what?
Nystagmus (eyes back and forth)
What is the major output from Cerebellar nuclei?
SCP
What are the major inputs to the Cerebellar cortex.
Vermis = Fastigial
Medial hemi. = interposed
Lateral Hemi = dentate
One side of cerebellum affects _______ limbs.
Ipsilateral
One Cerebral hemisphere controls ________ muscles.
Contralateral
Cerebellum projects to _______ thalamus.
Contralateral
