BrainComponentCerebellum

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Cerebellum

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Divisions

Cerebellum consists of:

  • Fastigial Nucleus
  • Globose Nucleus
  • Emboliform Nucleus
  • Dentate Nucleus
  • Cerebellum Cortex
  • Interposed Nucleus = Globose Nucleus + Emboliform Nucleus

Diagrams

Neurons:

F18-3.png

Connections:

F18-4.png

Cerebellum Cortex

Cerebellum Cortex consists of:

  • Medial=Vermal (projects to Fastigial Nucleus)
  • Intermediate=Paravermal (projects to Interposed Nucleus)
  • Lateral=Hemisphere (projects to Dentate Nucleus)

Cerebellum Lobes:

  • Archicerebellum=Vestibulocerebellum (vermis) - vestibular->body
  • Paleocerebellum=Spinocerebellum (vermal, paravermal) - body->body
  • Neocerebellum (posterior) - cerebral cortex->body

Cortex Layers:

  • Molecular layer (outer)
  • Purkinje cell layer
  • Granular layer

Cerebellum Neurons

  • granular cells (total 100G) - like "T"
    • 4-6 short dendrites
    • axon goes to molecular layer and bifurcates into 2 branches
    • branches go in opposite directions
    • branches have excitatory synapses with Purkinje cells dendrites
  • Purkinje cell - the only output of CR
    • each Purkinje cell receives synapses from thousands of parallel fibers
    • Purkinje cell projects to CR nuclei as inhibitory
    • recurrent axon collaterals have inhibitory connections with other Purkinje cells
  • cerebellum nuclei exert excitary influences on muscles

Cerebellum Inputs

Climbing Fibers:

  • arrive from inferior olivary nucleus
  • excitatory to cerebellum cortex Purkinje cells
  • excitatory to cerebellum nuclei
  • each fiber divides into 10 branches within granular layer
  • branches go to molecular layer and synapse with Purkinje cells
  • each branch has several hundreds of synapses
  • one branch contacts several Purkinje cells
  • one Purkinje cell receives input from only one climbing fiber

Mossy Fibers:

  • originate from SC, vestibular, trigeminal, pontine, bRF
  • excitatory to granule cells
  • excitatory to cerebellum nuclei

Raphe Nucleus:

  • to cerebellar nuclei
  • to cerebellar cortex

Locus Ceruleus:

  • to Purkinje cells