The cerebellum Flashcards
What is the function of the cerebellum?
Voluntary movement
Posture and equilibrium
Primary inhibitory function
What are the cerebellar inputs?
Mossy fibers from corticopontocerebellar pathway, spinocerebellar pathway, reticular nuceli (BS), and vestibular nuceli (BS)
Climbing fibers from the inferior olive of medulla
What are the 5 types of neurons throughout the cerebellar cortex?
Stellate cells (inhibit)
Basket cells (inhibit)
Golgi cells (inhibit)
Granule cells (excite)
Purkinje cells (inhibit)
What does the outermost (molecular layer) consist of?
Granule cell axons (parallel fibers)
Dendrites of neurons in deeper layers
Scattered inhibitory interneurons (stellate and basket cells)
What fibers can excite the cerebellar neurons?
Mossy and climbing fibers
What are the deep 3 nuclei?
Vermis
Lateral zone
Intermediate
Recieve inputs from sensory afferent tracts and from the cerebellar cortex
Vermis
Vermis –> fastigial –> vestibular and reticular nuclei
Lateral zone
LZ –> denate –> thalamus, red nucelus and cerebral cortex
Intermediate
Intermediate –> interposed –> thalamus and red nucelus
Vestibulocerebellum
Helps coordinate balance and eye movement
Pathway: vestibular sensory –> flocculo-nodular –> vestibular motor–> alpha and gamma motorneurons –> BS and SC
Spinocerbellum
Helps coordinate muscle tone and limb movement
Pathway: red nucleus and reticular formation, alpha motorneurons, SC. BS, and SC (not order)
Cerebrocerebellum
Helps with planning coordinated, properly timed movement sequences
Pathway: red nucleus, alpha neurons,
Cerebellar diseases
Causes movement abnormalities like wide-based gait, ataxia, dysmetria
What is dysmetria manifested as?
Inability to target mouth on food
Exaggerated goose-stepping
Asynergia (complex movements uncoordinated)
Intention tremor (oscillating movement, worse during movement)
Nystagmus (rapid movement of eye)
Effects of small lesions
Produce no or transient symptoms
Other parts of the brain will compensate for deficit
