Magnetoencephalographic recordings demonstrate attentional modulation of mismatch-related neural activity in human auditory cortex.
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.
Woldorff
M G
MG
Research Imaging Center, University of Texas Health Science Center, San Antonio 78240-6240, USA. mwoldorff@uthscsa.edu
Hillyard
S A
SA
Gallen
C C
CC
Hampson
S R
SR
Bloom
F E
FE
D000161:Acoustic Stimulation; D000328:Adult; D001288:Attention / Q000502:physiology*; D001303:Auditory Cortex / Q000502:physiology*; D004007:Dichotic Listening Tests; D005072:Evoked Potentials, Auditory / Q000502:physiology; D006801:Humans; D015225:Magnetoencephalography