Cortisol Effects on Attentional Processes in Man as Indicated by Event‐Related Potentials

Glacocorticoids which are secreted from the adrenal cortex, particularly in response to stressful stimuli, are assumed to influence brain functions related to stimulus perception and processing. To determine underlying mechanisms of this action the present study investigated the effects of physiologically enhanced plasma glucocurticoid levels on auditory event‐related potentials (AERPs) reflecting different aspects of stimulus processing. Sixteen male adult subjects were tested in a dichotic listening paradigm containing four types of tone pips: standard and deviant target pips, which the subject either had to attend to, or to ignore. AERPs to the tone pips provided measures of different perceptual and attentional processes. Subjects were tested in a double‐blind fashion according to a within‐subject cross‐over design under either 16 mg hydrocortisone, infused over the experimental period of 1 hrs, or placebo. Compared to placebo sessions, under cortisol treatment a slightly decreased amplitude of the N1 component was obtained independently of the type of tone pip presented. In addition, mismatch negativity, measured as the difference amplitude between AERP waveforms to standard and deviant target pips in the unattended ear, was substantially reduced by hydrocortisone. Results support an inhibitory action of enhanced plasma cortisol levels on stimulus processing mediated by the nonspecific sensory system.