title: Modeling the influence of short term depression in vesicle release and stochastic calcium channel gating on auditory nerve spontaneous firing statistics.
abstract: We propose several modifications to an existing computational model of stochastic vesicle release in inner hair cell ribbon synapses, with the aim of producing simulated auditory nerve fiber spiking data that more closely matches empirical data. Specifically, we studied the inter-spike-interval (ISI) distribution, and long and short term ISI correlations in spontaneous spiking in post-synaptic auditory nerve fibers. We introduced short term plasticity to the pre-synaptic release probability, in a manner analogous to standard stochastic models of cortical short term synaptic depression. This modification resulted in a similar distribution of vesicle release intervals to that estimated from empirical data. We also introduced a biophysical stochastic model of calcium channel opening and closing, but showed that this model is insufficient for generating a match with empirically observed spike correlations. However, by combining a phenomenological model of channel noise and our short term depression model, we generated short and long term correlations in auditory nerve spontaneous activity that qualitatively match empirical data.
authors.affiliation: Computational and Theoretical Neuroscience Laboratory, Institute for Telecommunications Research, University of South Australia Mawson Lakes, SA, Australia.
authors.forename: Bahar
authors.initials: B
authors.lastname: Moezzi
authors.affiliation: Computational and Theoretical Neuroscience Laboratory, Institute for Telecommunications Research, University of South Australia Mawson Lakes, SA, Australia.
authors.forename: Nicolangelo
authors.initials: N
authors.lastname: Iannella
authors.affiliation: Computational and Theoretical Neuroscience Laboratory, Institute for Telecommunications Research, University of South Australia Mawson Lakes, SA, Australia.
authors.forename: Mark D
authors.initials: MD
authors.lastname: McDonnell
keywords: auditory nerve; calcium dynamics; channel noise; inner hair cell; neural variability; short term depression; stochastic synapse