Granule Cell

Cellula granularis

The most abundant neuron in the brain, tiny, glutamatergic cerebellar cells whose parallel-fiber axons run orthogonally through the Purkinje dendritic array.

Function

Glutamatergic, excitatory. Receive mossy fiber input and relay it through parallel fibers to Purkinje cells. The divergent mossy-fiber / parallel-fiber architecture is the anatomical basis of the Marr-Albus-Ito theory of cerebellar learning: each Purkinje cell samples a vast patch of granule-cell input space and learns a sparse pattern through LTD.

Morphology

Tiny (~6 µm) soma with three or four short claw-like dendrites that form rosette-like contacts with mossy fiber terminals inside glomeruli. The single ascending axon bifurcates into a T-shape, producing the characteristic parallel fibers of the molecular layer.

Specification

  • Neurotransmitter: Glutamate
  • Receptors: NMDA; GABA-A
  • Location: Granular layer of the cerebellar cortex.
  • Projections: Purkinje cells (via parallel fibers)
  • Firing: Sparse firing
  • Markers: GABRA6; SLC17A7/VGLUT1; ZIC1/ZIC2; PAX6 and ATOH1 (developmental); NeuN (generic)
  • Developmental origin: Rhombic lip (Cerebellar)
  • Disease: Medulloblastoma; Epilepsy
  • Cell Ontology: CL:0001031

References

  1. Azevedo FAC et al. (2009). Equal numbers of neuronal and nonneuronal cells make the human brain an isometrically scaled-up primate brain.. Journal of Comparative Neurology 513 PMID 19226510

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