CB Flashcards
(42 cards)
What are the general functions of the cerebellum?
- regulate equilibrium
- muscle tone and posture
- motor coordination for voluntary mvmts (modifies motor programs in response to environmental changes)
What are the two main fissures of the cerebellum and what do they separate?
posterolateral fissure: separates flocculunodular area from rest of cerebellum
primary fissure: anterior/posterior divisions
What are the deep nuclei of the cerebellum?
dentate
interposed (emboliform, globose)
fastigal
Inferior cerebellar peduncle restiform body
inputs from spinal cord, brainstem
monitors muscle and limb mvmt
ICP juxtarestiform body
interconnects vestibular nuclei and cerebellum
imp for head/eye mvmt
middle cerebellar peduncle
largest, located lateral to pons
gets afferents from: CONTRA basis pontis
relays motor signals from cerebral cortex to cerebellum
superior cerebellar peduncle
mostly EFFERENT fibers
fibers go to red nucleus, thalamus
DECUSSATES
exception to “outflow from SCP” rule: anterior spinocerebellar tract uses SCP to enter cerebellum
How is the cerebellum somatotopically arranged?
fractioned somatotopy
dif parts of body show up multiple dif places
What is the general pattern for how info from the spinal cord and brainstem get into the cerebellum?
- info enters from SC, BS on mossy fibers via ICP and MCP
- synapse in granule layer
- synapse in molecular layer on purkinje cells (PKC)
- synapse in deep cerebellar nuclei
- go to either:
a) red nucleus and thalamus (VL) via SCP
b) vestibular nuclei via ICP
What is the general pattern for how info from the inferior olivary nucleus (ION) gets into the cerebellum?
- info from ION leaves on climbing fibers via ICP
- synapse in molecular layer on PKC
- synapse in deep cerebellar nuclei
- go to either:
a) red nucleus and thalamus (VL) via SCP
b) vestibular nuclei via ICP
What are the three layers of the cerebellar cortex and are they uniform throughout?
yes uniform
from top to bottom:
molecular layer
PKC layer
granule layer
Do climbing fibers from ION synapse in granule layer?
no
What are the excitatory cells of the cerebellar circuit?
mossy fiber
climbing fiber
What are the inhibitory cells of the cerebellar circuit?
stellate
basket
golgi
PKC
What do stellate and basket cells do?
inhibit PKC
What do golgi cells do?
inhibit granule cells
What happens once mossy fibers excite a group of granule cells?
- 100s of PKC are excited via parallel fibers
- PKC inhibit neurons in deep nuclei
- weakly facilitated PKC are edges of activated zone are turned off by stellate, basket cells to focus signal
- golgi cells in granule layer turn off initial signal
Do mossy and climbing fibers send collaterals to deep nuclei before the axon enters the cerebellar cortex?
yes
Where do PKC axons end?
deep nuclei of cerebellum
What CP does the anterior spinocerebellar tract use?
SCP
note: AST crosses midline 2x
What CP does the posterior spinocerebellar tract use?
ICP
What CP does the cuneocerebellar spinocerebellar tract use?
ICP
What CP does the pontocerebellar tract use
MCP
what CP does the olivocerebellar tract use
ICP
aka climbing fibers
