The cerebellum Flashcards
Cerebellum - Prominence
Accounts for 10% of total brain volume but more than HALF of the brain’s neurons
Cerebellar cortex - Key things
1) Consists of large number of virtually identical functional units suggesting that it performs similar functional operations on different inputs
2) It receives massive input from sensory systems and from systems involved in planning and execution of movement
3) Forms loops with premotor and motor systems of cerebral cortex and brainstem that are involved in controlling movement. It also has reciprocal connections with association cortex, especially in the frontal lobes
4) Synaptic transmission in the cerebellum is subject to modification (long term depression) which is thought to be important for motor learning
Damage to cerebellum causes…
Ataxia
Intention tremors
Decomposition of movements
Ataxia
Abnormalities in execution of voluntary movements. Lack of coordination
Intention tremors
Tremors DURING movements (diff from Parkinson’s) Most noticeable at the end of a movement
Decomposition of movement
Fragmentation of complex movements that are normally carried out in a smooth coordinated fashion
Folia
Folds in cerebellum
Increase the surface area of the cerebellar cortex
Flocculonodular region
Old structure
Balance and eye movements
Flattened under cerebellum
Spinocerebellum
Intermediate hemisphere - Vermis - Intermediate hemisphere
Gets most its inputs from spinal cord
Outputs go to brainstem and down spinal cord
Coordination of limbs
Vermis
Worm
Posture control
Intermediate hemispheres
Control limbs
Lateral hemisphere
Cerebrocerebellum
Communicates with cortex
Much bigger in humans
Some cognitive functions
Cerebellar peduncles
Connect the cerebellum to the brainstem
Superior peduncle
Middle cerebellar peduncle
Inferior cerebellar peduncle
Inferior cerebellar peduncle
Inputs from spinal cord (directly and through brainsten) and vestibular nuceli
Middle cerebellar peduncle
Huge ones
Inputs from cerebral cortex by way of PONTINE (pons) nucleus
Superior cerebellar peduncle
The output of cerebellum to brainstem and thalamus
Deep nuclei
Inputs to the cerebellum project to both the cortex and the deep nuclei
Outputs from the cortex project to the deep nuclei, which, in turn, form the outputs of the cerebellum
Fastigial
Outputs from Vermis, most medial pathways, balance and posture
Interposed
Inputs from intermediate hemispheres
Outputs go for cortex and rubrospinal tract limb control
Dentate nucleus
Go back up to thalamus and then to cerebral cortex