Mechanisms and functional roles of glutamatergic synapse diversity in a cerebellar circuit.

Published online

Journal Article

Synaptic currents display a large degree of heterogeneity of their temporal characteristics, but the functional role of such heterogeneities remains unknown. We investigated in rat cerebellar slices synaptic currents in Unipolar Brush Cells (UBCs), which generate intrinsic mossy fibers relaying vestibular inputs to the cerebellar cortex. We show that UBCs respond to sinusoidal modulations of their sensory input with heterogeneous amplitudes and phase shifts. Experiments and modeling indicate that this variability results both from the kinetics of synaptic glutamate transients and from the diversity of postsynaptic receptors. While phase inversion is produced by an mGluR2-activated outward conductance in OFF-UBCs, the phase delay of ON UBCs is caused by a late rebound current resulting from AMPAR recovery from desensitization. Granular layer network modeling indicates that phase dispersion of UBC responses generates diverse phase coding in the granule cell population, allowing climbing-fiber-driven Purkinje cell learning at arbitrary phases of the vestibular input.

Full Text

Duke Authors

Cited Authors

  • Zampini, V; Liu, JK; Diana, MA; Maldonado, PP; Brunel, N; Dieudonné, S

Published Date

  • September 19, 2016

Published In

Volume / Issue

  • 5 /

PubMed ID

  • 27642013

Pubmed Central ID

  • 27642013

Electronic International Standard Serial Number (EISSN)

  • 2050-084X

Digital Object Identifier (DOI)

  • 10.7554/eLife.15872

Language

  • eng

Conference Location

  • England