Modulation of the Auditory Cortex during Speech: An MEG Study

TLDR

Speech perception and production interact significantly, as shown by behavioral and imaging studies. The study examined how auditory cortical responses differ during self‑produced speech versus altered feedback. MEG recordings were taken from both hemispheres while subjects spoke and heard controlled feedback, then compared to matched‑tape playback recordings, with evoked responses captured without movement artifacts. Self‑produced speech elicited weaker cortical responses than tape playback, as did tones, whereas gated noise responses were unchanged, indicating auditory cortex attenuates sensitivity and modulates activity according to expected feedback.

Abstract

Abstract Several behavioral and brain imaging studies have demonstrated a significant interaction between speech perception and speech production. In this study, auditory cortical responses to speech were examined during self-production and feedback alteration. Magnetic field recordings were obtained from both hemispheres in subjects who spoke while hearing controlled acoustic versions of their speech feedback via earphones. These responses were compared to recordings made while subjects listened to a tape playback of their production. The amplitude of tape playback was adjusted to match the amplitude of self-produced speech. Recordings of evoked responses to both self-produced and tape-recorded speech were obtained free of movement-related artifacts. Responses to self-produced speech were weaker than were responses to tape-recorded speech. Responses to tones were also weaker during speech production, when compared with responses to tones recorded in the presence of speech from tape playback. However, responses evoked by gated noise stimuli did not differ for recordings made during self-produced speech versus recordings made during tape-recorded speech playback. These data suggest that during speech production, the auditory cortex (1) attenuates its sensitivity and (2) modulates its activity as a function of the expected acoustic feedback.