Cerebellum
Overview
Located just below occipital lobe & behind brainstem
10% of the brain’s mass but more than 50% of its neurons!
Functions:
◦ Coordination of voluntary movement (SMOOTH)
◦ Maintenance of balance & posture
◦ Motor learning
◦ Cognition & language*
Vestibulocerebellum/ archicerebellum
Connections with vestibular nuclei = spatial awareness, posture, balance, ocular movement
Cerebellar peduncles
Bundles of axons carrying info in & out of cerrebellum
All IPSILATERAL!
Inferior (input)
Middle (input)
• Largest
• Connection to brainstem
Superior (input & output)
Dorsal & Ventral Spinocerebellar
Unconscious proprioception from LE
timing & coordination of movements (from inferior olive of midbrain)
Development
Rhobencephalon (hindbrain)--- to metencephalon
Spinocerebellum/ paleocerebellum
Multiple connections within CNS= monitors and fine tunes limb movements, regulates muscle tone
Cerebellar blood supply
Superior cerebellar artery (SCA)
Anterior inferior cerebellar artery (AICA)
Posterior inferior cerebellar artery (PICA)
Cuneocerebellar & Rostral Spinocerebellar
unconscious proprioception from UE
Red nucleus
limb coordination; which then sends info via rubrospinal tract
How does it influence movement
Like the BG, there are NO direct pathways to LMNs, therefore it can NOT initiate movement
Instead, it influences movement by communicating with the UMNs in the motor cortex→modifies motor commands being sent by the UMNs
Cerebrocerebellum/ neocerebellum
Connections to cortex= planning & timing of movements, cognition, language
Cerebellar communication
Cerebellum involved in feedforward and feedback for motor behaviors!
•Feedforward- gives guidance upon initial execution
•Feedback- gives guidance based on task completion
trigeminocerebellar
unconscious prop to face
Superior colliculus
eye movements; which then sends info via tectospinal tract
Cerebellar lobe division
Divided into 3 lobes: anterior, posterior, flocculonodular
Cortex= outer gray matter
Cerebellar nuclei = inner white matter Lots of fissures & gyri
Cerebellar Communication
Meassages in
◦ Movement commands
◦ Proprioception
◦ Visual input
◦ Vestibular information
Movement
Cerebrum- decider
BG- architect
Cerebellum- builder
Vestibulocerebellar
head position in space, balance (from vestibular nuclei)
Vestibular nuclei
balance & postural control; which then sends info via vestibulospinal tract
Anatomy
PURKINJE CELLS:
▪ Special neuron found only in the
cerebellar cortex
▪ Fan shaped with multiple
dendrites
▪ Most release GABA→inhibitory
control to regulate & coordinate movement
Messages out
◦ Planning/ correcting movement
◦ Execution of movement
◦ Balance
◦ Eye movements
Recticularcerebellar
integrated motor messages from cortex & brainstem (from reticular nuclei)
Corticopontocerebellar
copy of motor info from corticospinal and corticobulbar tracts (from frontal lobe)
Reticular nuclei & Thalamic motor
- planning & correcting movement, muscle tone regulation; which then sends info via reticulospinal tracts
-motor cortex; - unconscious proprioception; which then sends info via corticospinal tracts (VL NUC)
◦ *BG also sends info here!