[lingtalks] Emily Myers Talk at U.C.S.D

[Catherine Alioto]

U.C.S.D presents a talk by Emily Myers, Brown University
Thursday, February 8, 2007
12:00 - 2:00 pm
Applied Physics and Mathematics Building
Multimedia Room # 4301

TITLE:
Variance and Invariance: Neural Correlates of Phonetic Category Structure

ABSTRACT:
  A fundamental question in the speech perception literature is how 
listeners are able to map a highly variable acoustic signal onto an 
invariant representation of a phonetic category, for instance, how 
different exemplars of a sound such as [d] get mapped to a common 
invariant category 'd'. To this end, I will discuss three studies in 
which we examined the neural structures underlying the perception of 
phonetic category structure. These studies employed event-related 
fMRI while subjects performed a phonetic categorization task on 
stimuli which ranged along a voice onset time continuum (e.g. from 
/da/ to /ta/). In Experiment 1 we investigated whether activation 
patterns would show sensitivity to within-category acoustic-phonetic 
variability. In Experiment 2 we investigated whether the graded 
pattern of activation observed in Experiment 1 was the result of 
phonetic competition between categories or phonetic category 
"goodness". In Experiment 3, we explored the extent to which 
activation patterns were modulated by a shift in category boundary 
induced by the influence of lexical status. Results suggested a 
division of labor between anterior (bilateral IFG) and posterior 
(bilateral STG) structures, in that anterior regions were maximally 
responsive to more ambiguous tokens, and posterior areas were 
responsive to the typicality of the speech token as a member of its 
phonetic category. In addition, activation in posterior areas was 
shown to be influenced by effects of lexical status, suggesting that 
the speech processing system is permeable to the influence of 
higher-level, lexical factors.



Catherine Alioto
Assistant to the Chair
Academic Affairs Coordinator
University of California, San Diego
Department of Linguistics
AP&M Building
9500 Gilman Drive
La Jolla, California 92093-0108
(858) 534-3601

Catherine Alioto
Assistant to the Chair
Academic Affairs Coordinator
University of California, San Diego
Department of Linguistics
McGill Hall
9500 Gilman Drive
La Jolla, California 92093-0108
(858) 534-3601
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