Listening to speech in noisy scenes: Antithetical contribution of primary and non-primary auditory cortex

Abstract

AbstractInvasive and non-invasive electrophysiological measurements during “cocktail-party”-like listening indicate that neural activity in human auditory cortex (AC) “tracks” the envelope of relevant speech. Due to the measurements’ limited coverage and/or spatial resolution, however, the distinct contribution of primary and non-primary auditory areas remains unclear. Using 7-Tesla fMRI, here we measured brain responses of participants attending to one speaker, without and with another concurrent speaker. Using voxel-wise modeling, we observed significant speech envelope tracking in bilateral Heschl’s gyrus (HG) and middle superior temporal sulcus (mSTS), despite the sluggish fMRI responses and slow temporal sampling. Neural activity was either positively (HG) or negatively (mSTS) correlated to the speech envelope. Spatial pattern analyses indicated that whereas tracking in HG reflected both relevant and (to a lesser extent) non-relevant speech, right mSTS selectively represented the relevant speech signal. These results indicate that primary and non-primary AC antithetically process ongoing speech suggesting a push-pull of acoustic and linguistic information.