tress Differentially Modulates Fear Conditioning n Healthy Men and Women

ackground: Stress and stress hormones modulate emotional learning in rats and might have similar effects in humans. Theoretic ccounts of posttraumatic stress disorder (PTSD), for example, implicate the stress-induced modulation of fear conditioning in the evelopment of intrusive emotional reactions. The present study examined the impact of acute stress and cortisol (CORT) on classically onditioned fear in men and women. ethods: Ninety-four healthy undergraduates were exposed to a mild stressor (or control condition) while subjective anxiety and lucocorticoid stress responses (salivary CORT) were measured. One hour later, all participants participated in a differential fear onditioning procedure while conditioned skin conductance responses (SCR) were recorded. esults: Exposure to the stressor increased subjective anxiety and elevated CORT levels. In men, stress exposure facilitated fear onditioning; whereas in women, stress appeared to inhibit fear conditioning. The impact of stress on differential conditioning in men as associated with increased CORT levels. onclusions: Consistent with animal models, these results demonstrate that stress exposure can modulate classical conditioning in umans, possibly via hormonal mechanisms. The enhancing effects of stress on the formation of conditioned fear might provide a seful model for the formation of pathological emotional reactions, such as those found in PTSD.