Precision and reliability of cochlear nerve response in mice lacking functional synaptic ribbons

[摘要] (cont.) stimulus phase was unimpaired, the time course of post-onset adaptation and recovery from adaptation were normal, and the ability to sustain discharge throughout a long-duration stimulus was unaffected. These data indicate that the presynaptic mechanisms which regulate precise timing of exocytosis, graded release rates and sustained neurotransmitter release were not impaired by loss of the ribbon. However, reductions were seen in spontaneous and sound-evoked AN fiber discharge rates, coinciding with an increased variance of first spike timing to stimulus onset. Unlike fibers from wild-type mice, mutants failed to show increased peak rate as stimulus onset became more abrupt. The reduction of peak rates and increased first spike variance likely result from degraded reliability of discharge to stimulus onset via a mechanism such as reduced RRP size. Thus, the ribbon appears to support a large RRP that enables the rapid onset rates necessary for the auditory system to resolve stimulus features key for many perceptual tasks.

[发布机构] Massachusetts Institute of Technology