HUMAN EVENT-RELATED BRAIN POTENTIALS TO AUDITORY PERIODIC NOISE STIMULI

Periodic noise is perceived as different from ordinary non-repeating n oise due to the involvement of echoic memory. Since this stimulus does not contain simple physical cues (such as onsets or spectral shape) t hat might obscure sensory memory interpretations, it is a valuable too l to study sensory memory functions. We demonstrated for the first tim e that the processing of periodic noise can be tapped by event-related brain potentials (ERPs). Human subjects received repeating segments o f noise embedded in non-repeating noise. They were instructed to detec t the periodicity inherent to the stimulation. We observed a central n egativity time-locked on the periodic segment that correlated to the s ubjects behavioral performance in periodicity detection. It is argued that the ERP result indicates an enhancement of sensory-specific proce ssing. (C) 1998 Elsevier Science Ireland Ltd.