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Onset coding is degraded in auditory nerve fibers from mutant mice lacking synaptic ribbons.

ABSTRACT: Synaptic ribbons, found at the presynaptic membrane of sensory cells in both ear and eye, have been implicated in the vesicle-pool dynamics of synaptic transmission. To elucidate ribbon function, we characterized the response properties of single auditory nerve fibers in mice lacking Bassoon, a scaffolding protein involved in anchoring ribbons to the membrane. In bassoon mutants, immunohistochemistry showed that fewer than 3% of the hair cells' afferent synapses retained anchored ribbons. Auditory nerve fibers from mutants had normal threshold, dynamic range, and postonset adaptation in response to tone bursts, and they were able to phase lock with normal precision to amplitude-modulated tones. However, spontaneous and sound-evoked discharge rates were reduced, and the reliability of spikes, particularly at stimulus onset, was significantly degraded as shown by an increased variance of first-spike latencies. Modeling based on in vitro studies of normal and mutant hair cells links these findings to reduced release rates at the synapse. The degradation of response reliability in these mutants suggests that the ribbon and/or Bassoon normally facilitate high rates of exocytosis and that its absence significantly compromises the temporal resolving power of the auditory system.

SUBMITTER: Buran BN

PROVIDER: S-EPMC2901931 | biostudies-other | 2010 Jun

REPOSITORIES: biostudies-other

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Onset coding is degraded in auditory nerve fibers from mutant mice lacking synaptic ribbons.

Buran Bradley N BN Strenzke Nicola N Neef Andreas A Gundelfinger Eckart D ED Moser Tobias T Liberman M Charles MC

The Journal of neuroscience : the official journal of the Society for Neuroscience 20100601 22

Synaptic ribbons, found at the presynaptic membrane of sensory cells in both ear and eye, have been implicated in the vesicle-pool dynamics of synaptic transmission. To elucidate ribbon function, we characterized the response properties of single auditory nerve fibers in mice lacking Bassoon, a scaffolding protein involved in anchoring ribbons to the membrane. In bassoon mutants, immunohistochemistry showed that fewer than 3% of the hair cells' afferent synapses retained anchored ribbons. Audito ...[more]

PMID: 20519533

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Onset coding is degraded in auditory nerve fibers from mutant mice lacking synaptic ribbons.

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Onset coding is degraded in auditory nerve fibers from mutant mice lacking synaptic ribbons.

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