Accelerated trace eyeblink conditioning after cortisol IV-infusion

Publication Type:

Journal Article


Neurobiol Learn Mem, Volume 94, Number 4, p.547-553 (2010)


1095-9564 (Electronic)10

DOI Name (links to online publication)



Impairing effects of cortisol on learning performance have been shown in human trace eyeblink conditioning. As the effect is observed from 30min to hours after administration, a genomic action of cortisol is assumed. Here we report rapid cortisol effects that were observed during the first 10min after cortisol administration in humans. Young healthy males (n=24) received the cortisol synthesis inhibitor metyrapone (1.5g per os) to avoid interference of the endogenous pulsatile secretion of cortisol. Next, 2mg 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, 50ms; conditioned stimulus: binaural pure tone, 75dB, 1000Hz, 400ms; empty interval between CS and US: 550ms). 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.