Cerebellum Flashcards
What is the cerebellum?
“little brain”. brain structure located in brainstem
What is one of the primary functions of the cerebellum?
to detect the difference or motor error between an intended movement and the actual movement to reduce the error
How does the cerebellum influence movement and balance?
by modifying the activity patterns of the upper and lower motor neurons
What are the two cerebellar hemispheres?
two; anterior and posterior lobe
What are the deep cerebellar nuclei?
clusters of cells in nuclei buried deep in the white matter of the cerebellum
What are the three cerebellar peduncles?
Superior, middle and inferior
Cerebellar hemispheres can be divided into what three parts?
cerebrocerebellum (lateral zone)
spinocerebellum (median zone)
Vestibulocerebellum (caudal-inferior zone, oldest part of cerebellum)
What is the spinocerebellum composed of?
Vermis (most median zone)
Paramedian zone
What is the vestibulocerebellum composed of?
flocculus and nodulus
The cerebrocerebellum receives input from what?
indirect input from many areas of the cerebral cortex
What are the functions of the cerebrocerebellum?
planning, coordination and execution of complex spatial and temporal sequences of movement, cognitive functions like timing, attention, etc
The spinocerebellum receives input from what?
direct input from the spinal cord (proprioceptive info)
What is the vermis involved with?
movement of the proximal muscles, movement of eyes
What is the paramedian zone involved with?
movement of distal muscles (arm and leg muscles
The vestibulocerebellum receives input from what?
from the vestibular nuclei in the brainstem
What are the functions of the vestibulocerebellum?
involved in regulation of movements that maintain posture, balance, equilibrium
What are the connections between the cerebellum and other parts of the nervous system made by?
made by the three large pathways called the cerebellar peduncles
What is the superior cerebellar peduncle?
mainly efferent pathways (output)
What is the middle cerebellar peduncle?
afferent pathways (input)
What is the inferior cerebellar peduncle?
Multiple pathways (afferent and efferent)
What does the corticopontocerebellar pathway do?
transmits info from motor, premotor cortex, somatosensory cortex via the pontine nuclei. Pathway enters the cerebellum through the middle cerebellar peduncle (fibers decussate).
Projects mostly to the cerebrocerebellum
What is the spinocerebellar pathway?
Transmit info from periphery via the spinal cord nuclei ==> projects to spinocerebellum ==> fibers enter cerebellum through the inferior cerebellar peduncle (do not decussate)
What information does the spinocerebellar pathway provide the cerebellum?
informs cerebellum of the momentary status of muscle contraction, tension, limb position and motion of the body
What is the vestibulocerebellar pathway?
transmit info from the vestibular pathway ==> projects to the vestibulocerebellum ==> fibers enter cerebellum through the inferior cerebellar peduncle (do not decussate)
What is the olivocerebellar pathway?
transmit info from cortex via red nucleus and inferior olive nucleus==> projects to cerebrocerebellum and deep nuclei ==> fibers enter cerebellum through inferior cerebellar peduncle (fibers decussate)
What do the inputs from the olivocerebellar pathway participate in?
Participate in the learning and memory functions served by cerebellar circuitry
What do the cerebellar cortex neuron project to?
project to the deep cerebellar nuclei
What do the deep cerebellar nuclei project to?
project out of cerebellum through the superior cerebellar peduncle into the primary motor & premotor cortex and towards the superior colliculus
What does the primary motor & premotor cortex participate in?
participates in planning and initiating voluntary movements
What does the superior colliculus do?
modulates the activity of the upper motor neurons concerned with eye movement
What does the cerebellum send its outputs into the vestibular nucleus through?
through the inferior cerebellar peduncle
What does the cerebellar-vestibular pathway allows the cerebellum to do?
to influence posture and equilibrium
Purkinje cells in the cerebellum receive what?
Receive sensory info from the inferior olive and pontine nuclei through the mossy fibers and climbing fibers
What do the purkinje cells do with the info they receive in the cerebellum?
process the info and compare the status of ongoing movement
What do the purkinje cells output after receiving info in the cerebellum?
send inhibitory projection onto the deep cerebellar nuclear cells ==> deep cerebellar nuclei send excitatory efferent onto motor cortex via the thalamus ==> cerebellar neurons output to the motor cortex generates an error correction signal to modify movement
What happens to purkinje cells and deep cerebellar nuclei cells when the wrist is at rest and when it is moving?
at rest: both are tonically active
During movement: both cell types receive a transient inhibition that blocks their tonic activity
What higher functions does the cerebellum have?
has a role in:
sensory acquisition
motor attention
timing of motor action
prediction and preparation of movement
motor sequence learning and memory
The cerebellum is considered a helper structure, what does it help with?
circuitry could be acting as a predictor and adjusts the body movements accordingly. It helps coordinate motor actions unconsciously
