Independence of early speech processing from word meaning

Katherine E. Travis, Matthew K. Leonard, Alexander M. Chan, Christina Torres, Marisa L. Sizemore, Zhe Qu, Emad Eskandar, Anders M. Dale, Jeffrey L. Elman, Sydney S. Cash, Eric Halgren

Research output: Contribution to journalArticlepeer-review

26 Scopus citations


We combined magnetoencephalography (MEG) with magnetic resonance imaging and electrocorticography to separate in anatomy and latency 2 fundamental stages underlying speech comprehension. The first acoustic-phonetic stage is selective for words relative to control stimuli individually matched on acoustic properties. It begins ∼60 ms after stimulus onset and is localized to middle superior temporal cortex. It was replicated in another experiment, but is strongly dissociated from the response to tones in the same subjects. Within the same task, semantic priming of the same words by a related picture modulates cortical processing in a broader network, but this does not begin until ∼217 ms. The earlier onset of acoustic-phonetic processing compared with lexico-semantic modulation was significant in each individual subject. The MEG source estimates were confirmed with intracranial local field potential and high gamma power responses acquired in 2 additional subjects performing the same task. These recordings further identified sites within superior temporal cortex that responded only to the acoustic-phonetic contrast at short latencies, or the lexico-semantic at long. The independence of the early acoustic-phonetic response from semantic context suggests a limited role for lexical feedback in early speech perception.

Original languageEnglish (US)
Pages (from-to)2370-2379
Number of pages10
JournalCerebral Cortex
Issue number10
StatePublished - Oct 2013
Externally publishedYes


  • ECoG
  • MEG
  • N400
  • Speech processing

ASJC Scopus subject areas

  • Cognitive Neuroscience
  • Cellular and Molecular Neuroscience


Dive into the research topics of 'Independence of early speech processing from word meaning'. Together they form a unique fingerprint.

Cite this