Unipolar Brush Cell

A neurons cell type of the human nervous system.

Specialized excitatory interneuron of the cerebellar granule layer and cochlear nucleus that amplifies local sensory (mossy-fiber) signals.

Function

Excitatory interneurons that amplify and prolong mossy-fiber signals, expanding granule-layer input dynamics; contribute to vestibular and cerebellar temporal processing.

Morphology

Unipolar; single short dendrite ending in a brush-like tuft of dendrioles forming a giant glutamatergic synapse with one mossy-fiber rosette

Specification

  • Neurotransmitter: Glutamate
  • Receptors: mGluR1 (GRM1) and mGluR2/3 (GRM2/GRM3) distinguish ON vs OFF UBC subtypes; AMPA mediates mossy-fiber input
  • Location: Cerebellar cortex (granular layer), densely in vestibulocerebellum; cochlear nucleus (granule cell domain)
  • Projections: Local intracortical; axons form intrinsic mossy-fiber-like terminals onto granule cells and other UBCs
  • Firing: Prolonged/graded amplifying responses to mossy-fiber input
  • Markers: EOMES/TBR2 (defining lineage TF); CALB2/calretinin (ON-UBC subset); GRM1 vs GRM2/3 (subtypes); glutamatergic (SLC17A6/VGLUT2, SLC17A7/VGLUT1). Marker expression is a continuum (Kozareva et al. 2021).
  • Developmental origin: Rhombic lip (EOMES+ progenitors)
  • Disease: Group 4 medulloblastoma resembles/arises from the UBC (EOMES+ rhombic-lip) lineage; early UBC transcriptional dysregulation in spinocerebellar ataxia type 1 (SCA1). (Tinnitus/vertigo plausible by location but not directly evidenced.)
  • Cell Ontology: CL:4023161

References

  1. Hendrikse LD et al. (2022). Failure of human rhombic lip differentiation underlies medulloblastoma formation.. Nature 609 PMID 36131014
  2. Kozareva V et al. (2021). A transcriptomic atlas of mouse cerebellar cortex comprehensively defines cell types.. Nature 598 PMID 34616064
  3. Tejwani L et al. (2024). Longitudinal single-cell transcriptional dynamics throughout neurodegeneration in SCA1.. Neuron 112 PMID 38016472

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