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

Authors

  • Marty G. Woldorff,

    Corresponding author
    1. Research Imaging Center and Department of Radiology, University of Texas Health Science Center, San Antonio, USA
      Address reprint requests to: Marty G. Woldorff, Ph.D., Research Imaging Center, University of Texas Health Science Center, 7703 Floyd Curl Drive, San Antonio, TX 78240-6240, USA. E-mail: mwoldorff@uthscsa.edu.
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  • Steven A. Hillyard,

    1. Department of Neurosciences, 0608, University of California–San Diego, La Jolla, USA
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  • Chris C. Gallen,

    1. Department of Neuropharmacology, Research Institute of Scripps Clinic, La Jolla, USA
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  • Scott R. Hampson,

    1. Department of Neuropharmacology, Research Institute of Scripps Clinic, La Jolla, USA
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  • Floyd E. Bloom

    1. Department of Neuropharmacology, Research Institute of Scripps Clinic, La Jolla, USA
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Address reprint requests to: Marty G. Woldorff, Ph.D., Research Imaging Center, University of Texas Health Science Center, 7703 Floyd Curl Drive, San Antonio, TX 78240-6240, USA. E-mail: mwoldorff@uthscsa.edu.

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.

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