EVENT-RELATED ALPHA-OSCILLATIONS ARE FUNCTIONALLY ASSOCIATED WITH P300 DURING INFORMATION-PROCESSING

RECENT findings indicate that the electroencephalographic alpha (7-14 Hz) activity is functionally involved in cognitive brain functioning, but the issue of whether and how event-related alpha oscillations may relate to the processes indexed by the P300 component of the event-rel ated brain potentials (ERPs) has not been addressed. The present study assessed the effect of auditory oddball task processing on slow (7-10 Hz) and fast (10-14 Hz) alpha activity from the P300 latency range. E RPs from mentally counted targets (20%) and uncounted non-targets (80% ) were recorded at Fz, Ct, and Pt in nine subjects Single-sweep phase- locking, power of phase-locked, and power of non-phase-locked alpha re sponses during P300 activity were quantified. The results demonstrated that larger and more synchronized phase-locked fast alpha components at anterior (frontal-central) locations, with reduced non-phase-locked slow alpha responses at the parietal site were produced by targets re lative to non-targets. Because the simultaneously recorded P300 and al pha activity manifested a similar sensitivity to the oddball task, eve nt-related alpha appears to be functionally associated with the cognit ive processing demands eliciting P300. Also, evidence is provided for the functional involvement of frontally synchronized and enhanced alph a oscillations in task processing. (C) 1998 Lippincott Williams & Wilk ins.