Magnetoencephalographic recordings demonstrate attentional modulation of mismatch‐related neural activity in human auditory cortex

TLDR

The 150–200 ms negative potential to a deviant sound can be modulated by attention. The study aimed to determine whether attentional modulation of the mismatch negativity originates in auditory cortex or elsewhere. Both MMN and MMF were recorded during a dichotic listening task to assess attentional effects. When attention was directed to the ear, a robust MMF originating in auditory cortex was observed, whereas MMN and MMF to unattended deviants were strongly attenuated, indicating that intensity‑based mismatch responses are gated by attention.

Abstract

It is widely agreed that the negative brain potential elicited at 150–200 ms by a deviant, less intense sound in a repetitive series can be modulated by attention. To investigate whether this modulation represents a genuine attention effect on the mismatch negativity (MMN) arising from auditory cortex or attention‐related activity from another brain region, we recorded both the MMN and the mismatch magnetic field (MMF) elicited by such deviants in a dichotic listening task. Deviant tones in the attended ear elicited a sizable MMF that was well modeled as a dipolar source in auditory cortex. Both the MMN and MMF to unattended‐ear deviants were highly attenuated. These findings support the view that the MMN/MMF elicited in auditory cortex by intensity deviants, and thus the underlying feature‐analysis and mismatch‐detection processes, are not strongly automatic but rather can be gated or suppressed if attention is strongly focused elsewhere.