Cerebellum Flashcards
Where is the cerebellum found?
Posterior cranial fossa
What is the name for the “gyri” of the cerebellum? In which direction do they run?
Folia
Mediolateral
What is the name of the midline part of the cerebellum?
Vermis
What are the names of the three lobes of the cerebellum?
What divides the anterior and posterior lobe?
Anterior, posterior and flocculonodular lobes
Primary fissure
Which part of the cerebellum forms part of the roof of the fourth ventricle?
Nodulus lobe
What is the most common site of an infarct in the posterior circulation?
PICA - posterior inferior cerebellar artery
What is the blood supply to the cerebellum? (3)
Posterior inferior cerebellar artery (PICA)
Superior cerebellar artery
Various branches of the basilar artery
How many layers does the cerebellar cortex have? Describe them.
Three
Outer molecular layer - pale with mostly axons & only a few cells
Middle layer - single row of ‘purkinje cells’
Inner layer - granule layer. Thick with a vast number of granule cells.
Inputs and outputs to cerebellum are via the…
Cerebellar peduncles
What are the three cerebellar peduncles called? What do they each do?
- Superior cerebellar peduncle - output fibres
- Middle cerebellar peduncle - input fibers from (contralateral) cerebral cortex and cranial nerves via pons
- Inferior cerebellar peduncle - input fibers from the spinal cord via dorsal and ventral spinocerebellar tracts
Is the dorsal (posterior) spinocerebellar tract ipsilateral or contralateral? Which peduncle does it enter? What type of information does it carry?
Ipsilateral
It enters the inferior cerebellar peduncle.
Proprioceptors from joints and muscle spindles
Is the ventral (anterior) spinocerebellar tract ipsilateral or contralateral in the spinal cord? What type of information does it carry?
Contralateral
It carries information about state of reflexes and inter-neurons in the spinal cord.
If a patient has a cerebellar lesion, the signs are always…
On the same side as the lesion
Describe what happens with the ventral (anterior) spinocerebellar tract in the spinal cord/brainstem.
It is contralateral in the spinal cord but then RECROSSES in the brain stem to end up on same side it enters cord. Information from the body is passed to the same side in the cerebellum.
What are the names of the deep cerebellar nuclei? Which nuclei connect to which parts of the cerebellum?
Fastigial (medial) - vermis
Globose - anterior lobe
Emboliform - anterior lobe
Dentate (lateral) - posterior lobe
What is the role of the deep cerebellar nuclei? Where are they found?
All inputs and outputs are routed through these nuclei - they receive input from afferents and send axons down the spinal cord or up to the motor thalamus (via the cerebellar cortex) in order to regulate movement.
They are found in the white matter below the cortex.
The different parts of the cerebellum link to the deep cerebellar nuclei. What does the flocculonodular lobe link to?
The lateral vestibular nuclei of the pons.
Does the cerebellum initiate movements?
What is it’s role in movement?
No.
It helps the motor cortex produce accurate and smooth movements by refining the motor cortex commands using feedback from proprioceptors & other sensory organs.