cerebellum Flashcards
cerebellum functions
- maintains balance and posture
- coordination of voluntary movements
- motor learning
- cognitive functions (?)
the cerebellum helps provide…
- coordination
- balance
- smooth body movement
feedback control of cerebellum
- information about the motor command coming from motor cortex goes to the cerebellum as the movement is progress
- there is feedback information coming from periphery (muscle spindles, skin surface, muscles, tendons, joints, etc.) about the movement to cerebellum
- cerebellum compares motor command to the periphery (what is intended vs the surrounding)
- cerebellum sends info to VA and VL
- VA and VL help control the motor cortex involved in descending tracts
folia
striations or tiny gyri of the cerebellum
= “leaf”
fissures of cerebellum
- primary
- posterolateral
primary fissure
separates anterior and posterior lobes of cerebellum
posterolateral fissure
separates flocculonodular lobe from posterior lobe
the posterior lobe of the cerebellum is the
largest
nodulus is AKA
flocculonodule lobe
lobes of cerebellum
- anterior
- posterior
- flocculonodular
flocculonodular lobe
floccular = lateral
nodular = central
vermis
areas of lobes
- vermis = central
- hemispheres = lateral
divisions of cerebellum
- vestibulo (archicerebellum)
- spino (paleocerebellum)
- cerebro (neocerebellum)
vestibulocerebellum
= flocculonodular lobe
- position in space
- in large animals like sharks
- most ancient
spinocerebellum
- gets feedback info from the spinal cord about limb position form the spinocerebellar tract
- vermis and anterior lobe of cerebellum
cerebrocerebellum
- sophisticated control of movement
- feed-forward
- most highly developed
- prominent in humans
- most direct feedback from cerebrum
histology of the cerebellum
- surface = grey matter
- inside = white matter
grey matter includes:
- granular layer
- purkinje cell layer
- molecular layer
granular layer contains
granule cells
# granular cells in cerebellum = # of granular cells in rest of brain
purkinje layer contains
single layer of purkinje cells
molecular layer contains
dendrites and axons
purkinje cells
- complex structure
- dendrites are organized in one plane
- lots of branching
cerebellar cortex circuitry
- granule cells receive info from pontine nuclei (mostly)
- synapse on granule cells
- axons go up into molecular layer
- parallel fibers (like telephone wires going through dendritic tree of purkinje cells)
deep cerebellar nuclei are located
- in white matter of cerebellum
deep cerebellar nuclei include
- fastigial nucleus - into spinocerebllum
- dentate nucleus - into cerebrocerebellum
- interposed nuclei - into vestibulocerebellum
cerebellar circuitry
- purkinje cells have inhibitory output to the deep cerebellar nuclei
- deep cerebellar nuclei signal to VA and VL
feedback within the lobes of cerebellum
(page 39 of old scribe notes for more info)
pontine nuclei get info from the
motor track
- then go to opposite cerebellar peduncle
- then to cerebellum
cerebellar lesions can cause
- loss of balance
- ataxia
- decomposition of movement
- dysdiadochokinesis
- intention tremor
- dysmetria
- dysarthria
- nystagmus
- hypotonia
ataxia
- uncoordinated walking (gait)
- like a drunken walk
decomposition of movement
- lack of coordination of shoulder and elbow joint
dysdiadochokinesis
- patient is asked to flip hand rapidly
- cannot do so
intention tremor
- test: close eyes touch your nose
- in patients, they have a strange path due to tremor of movement and overshoot the location
dysmetria
trouble reaching a target
dysarthria
trouble controlling muscles of speech
nystagmus
oscillation of the eyes
hypotonia
decreased muscle tone
lesions in different areas and the disorders caused by lesion of that location
vestibulocerebellum lesion causes
- loss of balance
- vertigo
- nystagmus
spinocerebellum lesion causes
- intention tremor
- dysmetria
- ataxia
cerebrocerebellum lesion causes
- decomposition of movement
