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Speech Sound Representation in the Auditory Nerve: Computer Simulation Studies on Inner Ear Mechanisms
Author(s) -
Rattay F.,
Lutter P.
Publication year - 1997
Publication title -
zamm ‐ journal of applied mathematics and mechanics / zeitschrift für angewandte mathematik und mechanik
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.449
H-Index - 51
eISSN - 1521-4001
pISSN - 0044-2267
DOI - 10.1002/zamm.19970771212
Subject(s) - quasiperiodic function , basilar membrane , aperiodic graph , acoustics , process (computing) , computer science , signal (programming language) , speech recognition , representation (politics) , physics , cochlea , neuroscience , psychology , mathematics , politics , combinatorics , programming language , condensed matter physics , operating system , political science , law
Abstract Acoustical signals are represented in the auditory nerve both by place‐rate information and by the fine structure of the time differences in the spiking pattern. For those parts of human speech which are quite aperiodic the place‐rate information is very poor, because the mechanical tuning process needs time. Computer simulation of inner ear mechanics shows that the onset of a signal moves all parts of the basilar membrane. Plenty of fibers coming from all regions will be stimulated by the first pressure wave. Because of the rapid neural adaptation process even fibers with high characteristic frequencies are systematically activated by low frequency speech components. The time structure of the firing pattern seems to be of much higher significance than previously assumed. It is also of importance for the quasiperiodic parts of speech. Irregularities in speech and sound level are the reasons, why signal processing is not governed by the sharp tuning properties of auditory fibers which are known from stimulations with pure periodic signals of low level.