Cerebellum

Consists of

3 main parts

going outwards???

divided by two deep transverse fissures

• vestibulocerebellum (aka flocculonodular lobe, archicerebellum)
• spinocerebellum (aka anterior cerebellum, paleocerebellum)

  vermis (trunk, posture, locomotion)

  intermediate cerebellar hemispheres (proximal)

• cerebrocerebellum (aka posterior cerebellum, lateral cerebellar hemispheres, neocerebellum)

3 functionally distinct regions

• cerebellar cortex

  outer mantle of gray matter

• internal white matter
• deep cerebellar nuclei

Located in

inferior posterior portion of the head (hindbrain)

dorsal to the pons and inferior to the occipital lobe

Inputs from

cerebellar mossy fibers

climbing fibers

where else???

Sends to

connected to dorsal brainstem by 3 symmetrical pairs of tracts (peduncles = fiber bundles)

• superior cerebellar peduncle
• middle cerebellar peduncle
• inferior cerebellar peduncle

where else???

Function

integration of sensory perception and motor output

involved in classical conditioning

and operant conditioning

vestibulo-ocular reflex

Details

contains nearly 50% of all neurons, though only 10% of volume

highly uniform cytoarchitecture

repeating circuit, but different areas have different inputs

may be performing the same computation on different inputs

comparing intention with action, and adjusting motor output to compensate

40 times more axons go into the cerebellum as come out of it

specific motor disorders

cerebellar hypotonia

tremor in pendular reflexes, e.g knee jerk reflex

ataxia

delay in initiating responses

dysmetria

intention tremors (occur during movement)

dysmetria - under/overestimate force

damage to cerebellum affects

walking

balance

accurate hand + arm movement

lateralization

anterior and medial cerebellum represents stuff ipsilaterally

posterior and lateral cerebellum represents bilaterally

sometimes cerebellar lesions can disrupt ipsilateral movement (because tracts cross contralaterally twice)

involved in dyslexia and autism???

imaging

language processing

selective attention

Theories

vestibulo-ocular reflex and classical conditioning (eyeblinks)

see thompson

learning machine

marr & albus - see marr#cerebellum

LTD of parallel fibers

tensor network theory (Pellionisz & Llinas)

transformation of sensory (covariant) space-time coordinates into motor (contravariant) coordinates

Etymology

cerebellum = 'little brain' in Latin

From sara notes

The cerebellum has three functionally distinct regions:

1. vestibulocerebellum (aka, flocculonadular node flocculus): controls balance and eye movments.
2. spinocerebellum

   vermis:

   runs along midline. Latin for worm. Governs posture and locomotion and gaze. To festigial nuclei.

   intermediate hemispheres.

   Receive somatosensory input. From interposed nucleus to lateral corticospinal and rubrospinal system. Controls distal muscles of limbs and digits.

3. cerebrocerebellum (lateral hemispheres). Evolutionarily the youngest. Received input exclusively from the cerebral cortex. Involved in planning and mental rehearsal of complex motor actions and conscious assessment of movement errors.