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Neural dynamics of variable-rate speech categorization.

S Grossberg·I Boardman·M Cohen
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Abstract

What is the neural representation of a speech code as it evolves in time? A neural model simulates data concerning segregation and integration of phonetic percepts. Hearing two phonetically related stops in a VC-CV pair (V = vowel; C = consonant) requires 150 ms more closure time than hearing two phonetically different stops in a VC1-C2V pair. Closure time also varies with long-term stimulus rate. The model simulates rate-dependent category boundaries that emerge from feedback interactions between a working memory for short-term storage of phonetic items and a list categorization network for grouping sequences of items. The conscious speech code is a resonant wave. It emerges after bottom-up signals from the working memory select list chunks which read out top-down expectations that amplify and focus attention on consistent working memory items. In VC1-C2V pairs, resonance is reset by mismatch of C2 with the C1 expectation. In VC-CV pairs, resonance prolongs a repeated C.

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Computer SimulationHumansMemoryModels, PsychologicalPhoneticsSpeechJournal ArticleResearch Support, Non-U.S. Gov'tResearch Support, U.S. Gov't, Non-P.H.S.

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BibTeXRIS

S Grossberg, I Boardman, M Cohen. 1997. Neural dynamics of variable-rate speech categorization.. https://doi.org/10.1037/%2F0096-1523.23.2.481

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