Event-Related Potentials to Time-Deviant and Pitch-Deviant Tones

Authors

  • Helge Nordby,

    1. Laboratory of Clinical Psychopharmacology and Psychophysiology, V.A. Medical Center, Palo Alto, and Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, California
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    • Mr. Nordby's present address is Department of Somatic Psychology, Årstadveien 21, 5000 Bergen, Norway.

  • Walton T. Roth,

    Corresponding author
    1. Laboratory of Clinical Psychopharmacology and Psychophysiology, V.A. Medical Center, Palo Alto, and Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, California
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  • Adolf Pfefferbaum

    1. Laboratory of Clinical Psychopharmacology and Psychophysiology, V.A. Medical Center, Palo Alto, and Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, California
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  • This study was supported in part by the Medical Research Service of the Veterans Administration, NIMH grant MH 40052, and NIMH Special Research Center grant MH 30854.

Address requests for reprints to: Walton T. Roth, M.D., Psychiatry (116A3), V.A. Medical Center, 3801 Miranda Avenue, Palo Alto, California 94304, USA.

ABSTRACT

Twelve subjects were run in a paradigm designed to compare event-related brain potentials (ERPs) elicited by infrequent pitch-deviant and time-deviant tones under different attentional conditions. Tones with a pitch of 500 Hz or 1000 Hz were presented at regular interstimulus intervals of 800 ms. Changes in pitch or a shortening of interstimulus interval to 400 ms each occurred with 10% probability. Three different tasks (reading or reaction time to pitch or to timing deviances) were assigned on separate runs.

N150 to deviant tones was not influenced by task. Its amplitude, peak latency, and frontally maximum distribution did not differ between pitch and timing deviance, but to pitch deviance it had an earlier onset. P350 amplitude to both types of deviant tones was larger than to standard tones when subjects pressed to time-deviant tones; only P350 to pitch-deviant tones was larger than to standards when subjects pressed to pitch-deviant tones. P350 latency was longer to timing deviance regardless of task.

Our results support the view that negativities generated by mismatches in expected timing and pitch are qualitatively the same. ERP differences between these two types of deviance were probably due to differences in stimulus salience or discriminability.

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