Impairing effects of cortisol on learning performance have been shown in human trace eyeblink conditioning As the effect is observed from 30 min to hours after administration a genomic action of... Show moreImpairing effects of cortisol on learning performance have been shown in human trace eyeblink conditioning As the effect is observed from 30 min to hours after administration a genomic action of cortisol is assumed Here we report rapid cortisol effects that were observed during the first 10 min after cortisol administration in humans Young healthy males (n = 24) received the cortisol synthesis inhibitor metyrapone (1 5 g per os) to avoid Interference of the endogenous pulsatile secretion of cortisol Next 2 mg cortisol or placebo was infused intravenously immediately before the trace conditioning task The probability of the conditioned eyeblink responses was assessed electromyographically during the trace eyeblink conditioning task (unconditioned stimulus corneal air puff 10 psi 50 ms conditioned stimulus binaural pure tone 75 dB 1000 Hz 400 ms empty interval between CS and US 550 ms) Cortisol resulted in a faster increase of conditioning (p = 02) reaching a comparable level to placebo later on This result extends the well-known effects of stress on the quality and amount of learning by showing that cortisol also affects the speed of learning We propose that cortisol accelerates trace eyeblink conditioning via a fast non-genomic mechanism This fast action of cortisol is part of the adaptive strategy during the early stress response (C) 2010 Elsevier Inc All rights reserved Show less
