Flashcards in 1.57 Cerebellum Deck (40):
What is the function of the folia?
Increase surface area
What are the 2 cerebellar hemispheres involved in?
Involved in planning
What is the function of the vermis?
Ongoing monitoring of movement - motor control of the trunk musculature and some extremities
What si the function of the flocculonodular node?
involved in balance and vestibulo-occular reflexes
What is the function of the intermediate cerebellum?
distal muscles of the extremities
What is the function of the lateral part of the cerebellum?
motor planning of extremities
What part of the cerebellum projects into the dentate nucleus?
Where do pathways from the vermis project into?
Which nuclei does flucconudlar nodule project into?
the vestibular nucleus
What is the interposed nuclei made up of?
the embiloform and globose nuclei
So what are the four deep cerebellar nuclei?
Dentate, emboliform, globose and fastigal
Wha gives rise to climbing fibres?
fibres from the Inferior olivary nucleus to the cerebellum
What do other afferent fibres terminate as?
Which part of the cerebellum is related to the vestibulocerebellum pathway?
Flocculo-nodular lobe + part vermis
Explain the vestibulocerebellum...
Project onto the flocculo-nodular lobe
Input from vestibular nucleus, DSCT
Output to vestibular nuclei
What is the function of the vestibulocerebellum?
Posture and balance
Which part of the cerebellum is related to the spinocerebellar pathway?
vermis + fastigial nucleus + Intermediate part of hemisphere + globose, emboliform nuclei
Explain the spinocerebellar pathway...
Double decussation of the ASCT, enters through superioir peduncle, and no decussation of PSCT, enters through inferior peduncle
Pontine nuclei synapse
Fastigal and Globose nuclei
Info back to thalamus and cortex and output to body
Olive - send fibres into the same bit of cerebellum - info of proprioception
What is the function of the spinocerebellar pathway?
Updating ongoing movements
Which part of the cerebellum is involved in the cerebrocerebellar pathway (neocerebellum)?
lateral part of hemisphere + dentate nucleus
Explain the cerebrocellebelar pathway...
From non motor, planning cortex - frontal lobe etc
Input from posterior parietal cortex, inferior olivary nucleus
Synpases in the pons
The pontine nuclei send fibres across the pons to enter the contralateral cerebellum through the middle cerebellar peduncle
Output to premotor cortex, supplementary motor area via thalamus
What is the function of the neocerebellum pathway?
Initiation and planning of movements, motor learning
what are the inputs and outputs of the inferior olivary nuclei?
Inputs from all cortical regions and spinal cord
Outputs as climbing fibres to opposite cerebellum (through inferior cerebellar peduncle)
How are purknje fibres arranged?
Flat - 1 plane
Where are the purkinje fibres arranged?
These cells line up all long the folia - 2 inputs - mossy fibres (from everything except the olive).
Explain the granule cell layer...
high density of cellular nuclei
deep to this layer is the white matter of the cerebellum, which contains axons ascending to the cortex as well as axobs (parallel fibres) descending from the cortex to the deep cerebellar nuclei. The axons from granule layer run across the foli and throught the dendritic cells - each one would contains thousands of purkinje cells
Explain the climbing fibres...
each ends on one purkinje cell - 1:1 - purkinje layers info from pontine, largely planning, from inf. Olive they climb the dendritic tree - info from proprioception - excitatory
What is the parkunje cells output onto the deep cerebellar nuclei?
When can deep cerebellar nuclei be excitatory or inhibitory?
Thalamus - excitatory
Olive - inhibitory
How do parkunje fibres regulate the target nuclei?
when the parkunje fibres are activated, they can both inhibit or excite the target nuclei
Explain simple learning - conditioned eye blink...
Excitation E.g. a puff of air arrives at cerebellum via V cranial
Excitation - sound - arrives via inferior olive climbing fibres
Coincidence on Purkinje cell results in enhanced inhibition of deep cerebellar nucleus
Enhanced inhibition of deep cerebellar nucleus removes Inhibition from red nucleus and permits eye blink in response to sound
Learning takes place on the Purkinje cells
Projections of vestibulocerebellum pathway....
Fluccolonodular lobe + part of vermis
Reticular formation - reticulospinal tract
Lateral vestibular nucleus - vestibulospinal tract
Balance and control movements
Projections of the spinocerebellum pathway...
Emboliform and globose nuclei
Brain stem nuclei + red nuclei - axial and proximal muscles and distal limb muscles
Contralteral thalamus - control discharge of cortical neurones and planning movement and initiation
Projections of the corticocerebellum pathway...
Contraleteral thalamus - control discharge of cortical neurones and planning and movement initiation
Why can cerebellar disease occur?
alcohol misuse, toxicity, genetic disorders or traumatic experiences
What is a common symptoms?
Wide gait and difficulties balancing
Which pathway would a midline lesion affect?
What would a lesion in the vestibulocerebellum pathway result in?
○ Typically occurs bilaterally
○ Staggering gait (ipsilateral – falling to affected side)
Nystagmus on lateral gaze (contralateral)
What would a lesion in the spinocerebellum pathway result in?
Ataxia - uncoordinated movement - characterised by unsteady gait and uncoordinated limb movement
Smooth movement of limbs and coordination - touch nose then touch finger
Decomposition of movements (intention/action tremor))
Tremor of movement - not during rest