title: Stress differentially affects fear conditioning in men and women.
abstract: Stress and fear conditioning processes are both important vulnerability factors in the development of psychiatric disorders. In behavioral studies considerable sex differences in fear learning have been observed after increases of the stress hormone cortisol. But neuroimaging experiments, which give insights into the neurobiological correlates of stress × sex interactions in fear conditioning, are lacking so far. In the current functional magnetic resonance imaging (fMRI) study, we tested whether a psychosocial stressor (Trier Social Stress Test) compared to a control condition influenced subsequent fear conditioning in 48 men and 48 women taking oral contraceptives (OCs). One of two pictures of a geometrical figure was always paired (conditioned stimulus, CS+) or never paired (CS-) with an electrical stimulation (unconditioned stimulus). BOLD responses as well as skin conductance responses were assessed. Sex-independently, stress enhanced the CS+/CS- differentiation in the hippocampus in early acquisition but attenuated conditioned responses in the medial frontal cortex in late acquisition. In early acquisition, stress reduced the CS+/CS- differentiation in the nucleus accumbens in men, but enhanced it in OC women. In late acquisition, the same pattern (reduction in men, enhancement in OC women) was found in the amygdala as well as in the anterior cingulate. Thus, psychosocial stress impaired the neuronal correlates of fear learning and expression in men, but facilitated them in OC women. A sex-specific modulation of fear conditioning after stress might contribute to the divergent prevalence of men and women in developing psychiatric disorders.
authors.affiliation: Institute of Cognitive Neuroscience, Department of Cognitive Psychology, Ruhr-University Bochum, Universitätsstr. 150, 44780 Bochum, Germany; Bender Institute of Neuroimaging, Justus Liebig University Giessen, Otto-Behaghel-Str. 10H, 35394 Giessen, Germany. Electronic address: Christian.J.Merz@rub.de.
authors.forename: Christian Josef
authors.initials: CJ
authors.lastname: Merz
authors.forename: Oliver Tobias
authors.initials: OT
authors.lastname: Wolf
authors.forename: Jan
authors.initials: J
authors.lastname: Schweckendiek
authors.forename: Tim
authors.initials: T
authors.lastname: Klucken
authors.forename: Dieter
authors.initials: D
authors.lastname: Vaitl
authors.forename: Rudolf
authors.initials: R
authors.lastname: Stark
mesh_terms: D000328:Adult; D001921:Brain / Q000502:physiology; D001931:Brain Mapping; D003214:Conditioning, Classical / Q000502:physiology*; D005239:Fear / Q000502:physiology* / Q000523:psychology*; D005260:Female; D005712:Galvanic Skin Response / Q000502:physiology; D006801:Humans; D006854:Hydrocortisone / Q000378:metabolism; D008297:Male; D012463:Saliva / Q000378:metabolism; D012727:Sex Characteristics; D013315:Stress, Psychological / Q000503:physiopathology* / Q000523:psychology*; D000516:alpha-Amylases / Q000378:metabolism
chemical_list: D000516:alpha-Amylases; D006854:Hydrocortisone
keywords: Amygdala; Anterior cingulate; Cortisol; Fear learning; Nucleus accumbens; Oral contraceptives; Sex differences; Stress hormones; TSST; fMRI