Neuromagnetic mismatch fields to single and paired tones.
In 8 subjects we recorded multichannel magnetic responses to pitch changes in single 50 msec tones and in tone pairs (oddball paradigm; interstimulus interval 745 msec). Either "A" (1 kHz) was standard (90%) and "B" (1.2 kHz) deviant (10%), or "AA" was standard and "AB" deviant in pairs with onset asynchrony of 75 msec. Subject did not pay attention to the tones. A mismatch field (MMF) was evident in responses to deviants with an equivalent source in the supratemporal auditory cortex, about 1 cm anterior to that for N100m. The MMF source was 3-fold stronger for tone pairs than for single tones.
Low Temperature Laboratory, Helsinki University of Technology, Espoo, Finland.
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Hari
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Rif
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Tiihonen
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Sams
D000328:Adult; D001301:Audiometry, Pure-Tone; D001303:Auditory Cortex / Q000502:physiology; D005260:Female; D006801:Humans; D015225:Magnetoencephalography; D008297:Male; D011930:Reaction Time / Q000502:physiology; D012016:Reference Values; D012815:Signal Processing, Computer-Assisted