cerebellar anatomy

• what are the functional divisions of the cerebellum/where are they?


  1. spinocerebellum - coordinate motor movements and maintain tone
  2. cerebrocerebellum - planning movements and motor learning
  3. vestibulocerebellum - receives inputs from the vestibular nuclei in the brainstem and regulate balance and posture

  
• what are the Deep Cerebellar Nuclei and the Cerebellar Peduncles?


  DCN - nuclei that contain the output projection neurones, these project out to the brain through the peduncles

  Peduncles - axon tracts that link the cerebellum to the brain
• how many deep cerebellar nuclei and peduncles are there?

  three DCN

  three peduncles

  
• what are the higher and lower inputs into the cerbellum?


  lower inputs -> vestibular system, precerebellar system (from the body - Clarke's nucleus, external cuneate)

  upper inputs -> red nucleus, inferior olive, pontine nucleus

  
• on entering the spinal cord where do proprioceptive afferents synapse?


  in the ventral horn or up goes up through the spinal column
• outline conscious proprioceptive circuitry

  proprioceptive afferents into the dorsal horn, can synapse on the ventral horn or travel up

  synapse on the dorsal column nuclei -> pass through the medial leminsicus in the medulla -> decussates and synapses in the contralateral VP (L/M depending on case) nuclei in the thalamus and synpase -> thalamocortical projection to S1

  
• outline what happens in unconscious prorioceptive circuitry


  Upper body axons (thoracic and cervical) project to the external cuneate nucleus (next to the cuneate nucleus in the medulla).

  Lower body axons project to Clarke’s nucleus (C8 – L3).

  Both of these send projections to the cerebellum, which integrates proprioceptive information with descending motor commands (see week 3).

  
• how is balance consciously recognised? (conscious vestibular circuitry?)


  vestibular sensory neurons with cell bodies in vestibular ganglion, project to vestibular nuclei in the brainstem. Vestibular nuclei

  project to multiple nuclei in the thalamus. The thalamus projects

  to a distributed network of cortical areas that is involved in conscious

  vestibular sensation: S1 and vestibulocortical areas in the parietal, insular, and frontal lobes, all of which contribute to one’s sense of self in space.

  
• Unconscious Vestibular circuitry


  just like proprioception, there is conscious vestibular sensation computed in the cerebral cortex…

  …but also just like proprioception, there is unconscious vestibular sensation computed in the cerebellum (more specifically, the vestibulocerebellum – one of the three functional subdivisions of the cerebellum).
• the cerebellum contains as much as 80% of the neurones in the brain, what are their function 


  neurones do their associated functions like motor error-correction but also have been shown to play a big part in c]
• the cerebellum contains as much as 80% of the neurones in the brain, what are their function. What could a lesion cause


  neurones do their associated functions like motor error-correction but also have been shown to play a big part in cognition and sophisticated cortical function

  like motor right and left hand processes, language processing, mental arithmetic, saccades

  
  

  as well as the motor ability being affected it could affect the emotional regulation and thoughts of the person

  
• can someone live without a cerebellum?

  has been proof of individuals who have cerebellar agenesis -> never have had a cerebellum

  but if there is a lesion to the cerebellum of someone who has one it can have severe consequences
• what are the two subcortical 'feedback' systems that work to ensure smooth and correct functioning of the cerebral cortex

  basal ganglia and the cerebellum
• outline the three main cerebellar systems (paths and effect)

  here