title: A hardware model of the auditory periphery to transduce acoustic signals into neural activity.
abstract: To improve the performance of cochlear implants, we have integrated a microdevice into a model of the auditory periphery with the goal of creating a microprocessor. We constructed an artificial peripheral auditory system using a hybrid model in which polyvinylidene difluoride was used as a piezoelectric sensor to convert mechanical stimuli into electric signals. To produce frequency selectivity, the slit on a stainless steel base plate was designed such that the local resonance frequency of the membrane over the slit reflected the transfer function. In the acoustic sensor, electric signals were generated based on the piezoelectric effect from local stress in the membrane. The electrodes on the resonating plate produced relatively large electric output signals. The signals were fed into a computer model that mimicked some functions of inner hair cells, inner hair cell-auditory nerve synapses, and auditory nerve fibers. In general, the responses of the model to pure-tone burst and complex stimuli accurately represented the discharge rates of high-spontaneous-rate auditory nerve fibers across a range of frequencies greater than 1 kHz and middle to high sound pressure levels. Thus, the model provides a tool to understand information processing in the peripheral auditory system and a basic design for connecting artificial acoustic sensors to the peripheral auditory nervous system. Finally, we discuss the need for stimulus control with an appropriate model of the auditory periphery based on auditory brainstem responses that were electrically evoked by different temporal pulse patterns with the same pulse number.
authors: Special Research Promotion Group, Graduate School of Frontier Biosciences, Osaka University Osaka, Japan ; Biomedical Systems Engineering, Bioengineering and Bioinformatics, Graduate School of Information Science and Technology, Hokkaido University Sapporo, Japan.
authors: Takashi
authors: T
authors: Tateno
authors: Jun
authors: J
authors: Nishikawa
authors: Nobuyoshi
authors: N
authors: Tsuchioka
authors: Hirofumi
authors: H
authors: Shintaku
authors: Satoyuki
authors: S
authors: Kawano
keywords: acoustic sensor; computer model; digital signal processor; electrically evoked auditory brainstem response; piezoelectric film