Cerebellum Flashcards
Describe the location of the Cerebellum
Lies posterior to the 4th ventricle, pons and the medulla
The Cerebellum is separated from the brainstem via the 4th ventricle
What is the Tentorium Cerebelli?
It is membrane that separates the occipital lobe from the cerebellum
What are the Roles of the Cerebellum?
1) Modifies Balance
2) Coordination of posture and voluntary limb movement
3) Learned movements and motor planning (sequenced movement)
–> records errors in movements to create a better movement next time
What at the lobes of the Cerebellum?
Anterior (most superior)
Posterior (inferior)
Flocculonodular (in the middle - on the 4th ventricle side)
What are the regions of the Cerebellum?
Spinocerebellum
Vestibulocerebellum
Cerebrocerebellum
Describe Spinocerebellum
Made up of the vermis and paravermis
Vermis - modulates postural movements (Think midline structure = midline muscle innervation)
Paravermis - modulates voluntary movement in the distal limb
Output - to interposed nucleus and stimulates lateral pathways (eg rubrospinal and corticopsinal)
Describe Vestibulocerebellum
Made up of the flocculonodular lobe
involves and is important for the modulation of head eye movements
Output projects to the vestibular nuclei both in the ascending (vestibulocular) and descending (Vestibulospinal)
Describe the Cerebrocerebellum
Also known as the neocerebellum
- Involved in planning and learning movements
- provides conscious assessment of errors in movement
The most lateral part of the cerebellum
What is the Arbor Vitae?
Is the white matter of the cerebellum (houses myelinated axons)
Has a tree like appearance
What at the components of the deep cerebellum?
The Deep nuclei
1) Dentate - the most lateral - involved in motor planning and learning
2) Interposed - In the middle - responsible for limb voluntary movement
–> has 2 subdivision –> emboliform and globose
3) Fastigial - most medial - involved in postural muscle movements/adjustments
How does the cerebellum connect too the brainstem?
Connects via the 3 peduncles
1) superior peduncle - connects to midbrain (and thalamus)
2) middle peduncle - (the largest) - connects to pons
3) inferior peduncle - connects to medulla and lower areas
How does the cerebellum connect too the brainstem?
Connects via the 3 peduncles
1) superior peduncle - connects to midbrain (and thalamus)
2) middle peduncle - (the largest) - connects to pons
3) inferior peduncle - connects to medulla and lower areas
Describe the Cerebellar pathways (2)
Input –> deep cerebellum –> output
OR
Input –> Cerebellar cortex –> Deep Cerebellum –> output
Describe the Cerebrocerebellum pathway
Motor cortex –> Internal Capsule –> pons (crosses to otherside) –> cerebellum
What is the cerebro-rubrocerebellar loop?
signals sent from the cerebellum to the red nucleus –> project to the olives where errors in movement are detected. this error is sent to the cerebellum to be changed
form of insurance policy to ensure the correct movement is eventually emmited
Layers of the cerebellar cortex
Deepest - Granular layer
Middle - Purkinjee cells (they have large dendritic trees)
Top - Molecular layer
Describe the input fibre types to the cerebellum
Mossy fibres - arise from the spinal cord and the brainstem (except inferior olivary nuclei
Climbing fibres - arises from the inferior olivary nucleus
What is the role of climbing fibres
Stimulus of the climbing fibres causes a strong localised stimulus to be applied to the purkinjee cells to reconstruct the cel after an error in the movement. ensuring that next time the movement happens, the correct procedure of events takes place
What is the role of mossy fibres?
Provide general information of what is happening around us
What is the main role of the paravermis?
Innervates the distal limb muscles
recieves input from both somatosensory and motor cortex from stimulus from the periphery.
- compares both inputs and implements a sequence of events based on both the inputs
Outputs to the interposed nuclei and modulates the activity in the lateral tracts (e.g rubrospinal and corticospinal)
