Brennan, J., Lignos, Constantine, Embick, D. & Roberts, T. P. L. (2014). Spectro-temporal correlates of lexical access during auditory lexical decision. Brain & Language. 133:39–46.
DOI: 10.1016/j.bandl.2014.03.006
Lexical access during speech comprehension comprises numerous computations, including activation, competition, and selection. The spatio-temporal profile of these processes involves neural activity in peri-auditory cortices at least as early as 200ms after stimulation. Their oscillatory dynamics are less well understood, although reports link alpha band de-synchronization with lexical processing. We used magnetoencephalography to examine whether alpha-related oscillations reflect lexical activation. In an auditory semantic priming protocol, monosyllabic nouns were presented while participants performed a lexical decision task. Spatially-localizing beamforming was used to examine spectro-temporal effects in auditory cortex time-locked to target word onset. Alpha and beta de-synchronization (10-20Hz) was attenuated for words following a related prime compared to an unrelated prime beginning 270ms after stimulus onset. This timing is consistent with how information about lexical identity unfolds incrementally, quantified in information-theoretic terms. These findings suggest that alpha de-synchronization during auditory word processing is associated with early stages of lexical access