Phase-locking precision is enhanced by multiquantal release at an auditory hair cell ribbon synapse

Geng Lin Li, Soyoun Cho, Henrique von Gersdorff

Research output: Contribution to journalArticle

35 Scopus citations

Abstract

Sound-evoked spikes in the auditory nerve can phase-lock with submillisecond precision for prolonged periods of time. However, the synaptic mechanisms that enable this accurate spike firing remain poorly understood. Using paired recordings from adult frog hair cells and their afferent fibers, we show here that during sine-wave stimuli, synaptic failures occur even during strong stimuli. However, exclusion of these failures leads to mean excitatory postsynaptic current (EPSC) amplitudes that are independent of Ca2+ current. Given the intrinsic jitter in spike triggering, evoked synaptic potentials and spikes had surprisingly similar degrees of synchronization to a sine-wave stimulus. This similarity was explained by an unexpected finding: large-amplitude evoked EPSCs have a significantly larger synchronization index than smaller evoked EPSCs. Large EPSCs therefore enhance the precision of spike timing. The hair cells' unique capacity for continuous, large-amplitude, and highly synchronous multiquantal release thus underlies its ability to trigger phaselocked spikes in afferent fibers.

Original languageEnglish (US)
Pages (from-to)1404-1417
Number of pages14
JournalNeuron
Volume83
Issue number6
DOIs
StatePublished - 2014

ASJC Scopus subject areas

  • Neuroscience(all)

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