Modelling of the auditory ribbon synapse

ETCHEMENDY, PABLO ESTEBAN; VERGARA, RAMIRO OSCAR; EGUÍA, MANUEL CAMILO

Buenos Aires

Congreso; 22nd International Congress of Acoustics (POMA); 2016

International Commission for Acoustics (ICA)

The coding of the fine temporal details of auditory stimuli by the auditory system is required for many auditory tasks. For instance, the temporal information conveys information necessary for the perception of pitch and for the angular localization of sound sources. The first stage where this kind of information is processed is the auditory periphery. Inside the periphery, the ribbon synapse (RS) of auditory inner hair cells excels for its temporal acuity, a fact that has driven many recent physiological and computational studies. In this work we present a biophysical model of the auditory Ribbon Synapse (RS) of inner hair cells, which contains many anatomical details obtained from the electrophysiological data available in the literature, and is able to reproduce known features of the RS, namely, temporal adaptation of exocytosis due to partial vesicular depletion and gradual increment of the exocytosis rate as the membrane is depolarized. We used the model to study some aspects that are difficult to tackle experimentally, in particular, the influence of a vesicular fusion step on: (a) the formation of a "ring-like" spatial pattern of exocytosis, compatible with the spatial structure of postsynaptic receptors; and (b) the degree ofsynchronization of exocytosis as a function of release event size. The results described could be relevant in order to improve our knowledge of the temporal coding of auditory stimuli at the auditory periphery level.