The time-course of cortical responses to speech revealed by fast optical imaging

Joseph C. Toscano, Nathaniel D. Anderson, Monica Fabiani, Gabriele Gratton, Susan M. Garnsey

Research output: Contribution to journalArticlepeer-review


Recent work has sought to describe the time-course of spoken word recognition, from initial acoustic cue encoding through lexical activation, and identify cortical areas involved in each stage of analysis. However, existing methods are limited in either temporal or spatial resolution, and as a result, have only provided partial answers to the question of how listeners encode acoustic information in speech. We present data from an experiment using a novel neuroimaging method, fast optical imaging, to directly assess the time-course of speech perception, providing non-invasive measurement of speech sound representations, localized to specific cortical areas. We find that listeners encode speech in terms of continuous acoustic cues at early stages of processing (ca. 96 ms post-stimulus onset), and begin activating phonological category representations rapidly (ca. 144 ms post-stimulus). Moreover, cue-based representations are widespread in the brain and overlap in time with graded category-based representations, suggesting that spoken word recognition involves simultaneous activation of both continuous acoustic cues and phonological categories.

Original languageEnglish (US)
Pages (from-to)32-42
Number of pages11
JournalBrain and Language
StatePublished - Sep 2018


  • Event-related potentials
  • Optical imaging
  • Phonological categorization
  • Speech perception
  • Spoken language processing

ASJC Scopus subject areas

  • Experimental and Cognitive Psychology
  • Language and Linguistics
  • Linguistics and Language
  • Cognitive Neuroscience
  • Speech and Hearing


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