Time-intensity trading in the late auditory evoked potential

The present study investigated physiological correlates of the time-intensi ty trading relationship in late components (N1, P2) of the auditory evoked potential. Late-potential and behavioral thresholds were estimated in five normal-hearing, young adult participants for 1000- and 4000-Hz tone bursts having durations of 8, 16, 32, 64, and 128 ms. The results showed that late -potential thresholds decreased by an average of 24 dB for 1000-Hz conditio ns and 18 dB For 4000-Hz conditions. Behavioral thresholds also improved by about 22 dB and 18 dB for 1000-Hz and 4000-Hz conditions, respectively. Th e slope of improvement for both late-potential and behavioral thresholds wa s on the order of -4 to -6 dB per doubling of stimulus duration, depending on stimulus frequency. Stimulus duration also influenced latency and amplit ude measures of the N1 and P2 components such that response latency decreas ed and amplitude increased as stimulus duration increased. The present resu lts demonstrate a time-intensity trading relationship in components of the late potentials that is consistent with previous psychophysical and physiol ogical data.