Cortisol Effects on Averaged Evoked Potential, Alpha-Rhythm, Time Estimation, and Two-Flash Fusion Threshold

Eighteen normal male subjects, each serving as his own control, were tested with acute cortisol and placebo intravenous infusions on separate days. Previous studies have shown that enhancement of the amplitude of the averaged-evoked-potential by random flashes reflects selective attention. Cortisol administration was accompanied by a significant decrease in this enhancement. It is therefore hypothesized that cortisol may be acting to decrease the subject's ability to attend differentially to visual stimuli. Cortisol significantly increased the latency of the averaged-evoked-potential resulting from flashes when the subject attended to flashes. Several measures reflecting time perception were significantly changed by cortisol in a direction comparable with a slowed “internal clock”--ie, produced intervals were longer with the drug. Cortisol produced no changes in two-flash fusion threshold, mood adjective check list scores, and α-rhythm.