This thesis corroborates to a better understanding of the interplay between the brain and the hypothalamic-pituitary-adrenal (HPA) axis in response to acute psychosocial stress. Moreover, the impact of stress exposure time as well as gender differences were investigated. In a first step, a psychosocial stress paradigm suited for scanner environments – called ScanSTRESS – was evaluated and a hierarchical analysis strategy was developed. In the study proper, changes in brain activation, cortisol levels, affect, and heart rate responses to the improved ScanSTRESS protocol were assessed in 67 young, healthy participants (36 men, 31 women, all taking oral contraceptives; mean age 23.06 ± 3.14 years). Stress exposure led to significant increases in cortisol levels, heart rate, and negative affect ratings as well as activations and deactivations in (pre)limbic regions. When individual cortisol increases were used as covariate, stronger responses in the hippocampus, amygdala, medial prefrontal cortex, and cingulate gyrus were observed. Responses within the same regions predicted negative affect ratings throughout the protocol. Remarkably, an increasing deactivation over the two runs of ScanSTRESS was found, again, in the same structures. Regarding gender differences, responses of the hippocampus, amygdala, cingulate cortex, thalamus, and striatal structures were differentially associated with cortisol increases in women and men. For men, higher cortisol increases resulted in more activation of these striato-limbic structures whereas in women higher cortisol increases were associated with more deactivation
