The paradoxical increase in N1 amplitude to a repeated sound for intervals less than 300 ms is thought to reflect a process of temporal integration of rapid sounds within early auditory sensory memory (Cowan, 1984). The present study directly examined the temporal correspondence between N1 enhancements and a behavioural measure of temporal integration, auditory backward recognition masking (ABRM). Auditory ERPs were measured for 21 participants in response to brief sounds presented at random intervals (50 ? 1000ms ISI). N1 amplitude measures for three mid-line scalp sites (Fz Cz and Pz) as a function of inter-stimulus interval (ISI) were compared with a d-prime measure ofABRMperformance for target-mask intervals between 50 and 500ms. The results replicated previous ERP studies showing N1 enhancements at ISIs less than 300 ms. Similarly, ABRMperformance showed a dramatic decrease when target-mask interval was decreased below 300ms. Curve-fitting of d-prime and N1 x ISI function revealed a close correspondence between N1 amplitude at Fz only, and d-prime time constants for stimulus intervals between 50 and 500ms. The present results are consistent with previous claims that N1 enhancement reflects the integration of sensory information at rapid stimulus rates. These results are discussed in term of models of auditory sensory memory.
46th Annual Meeting of the Society for Psychophysiological Research. Poster Session Abstracts: 46th Annual Meeting of the SPR (Presented in Psychophysiology, Vol. 43, Supp. 1) (Vancouver, Canada 25-29 October, 2006) p. S28-S28