Major depressive disorder (MDD) is often accompanied by severe impairments in working memory (WM). Neuroimaging studies investigating the mechanisms underlying these impairments have produced conflicting results. It remains unclear whether MDD patients show hyper- or hypoactivity in WM-related brain regions and how potential aberrations in WM processing may contribute to the characteristic dysregulation of cognition-emotion interactions implicated in the maintenance of the disorder. In order to shed light on these questions and to overcome limitations of previous studies, we applied a multivoxel pattern classification approach to investigate brain activity in large samples of MDD patients (N = 57) and matched healthy controls (N = 61) during a WM task that incorporated positive, negative, and neutral stimuli. Results showed that patients can be distinguished from healthy controls with good classification accuracy based on functional activation patterns. ROI analyses based on the classification weight maps showed that during WM, patients had higher activity in the left DLPFC and the dorsal ACC. Furthermore, regions of the default-mode network (DMN) were less deactivated in patients. As no performance differences were observed, we conclude that patients required more effort, indexed by more activity in WM-related regions, to successfully perform the task. This increased effort might be related to difficulties in suppressing task-irrelevant information reflected by reduced deactivation of regions within the DMN. Effects were most pronounced for negative and neutral stimuli, thus pointing toward important implications of aberrations in WM processes in cognition-emotion interactions in MDD.

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Background: Previously, we found that patients with borderline personality disorder (BPD) but not healthy controls (HC) showed improved memory retrieval after hydrocortisone administration.Objective: In this study, we examined whether increases in endogenous cortisol after psychosocial stress are associated with memory function in patients with BPD and in healthy individuals.Methods: We recruited 49 female patients with BPD and 49 female HC. All participants were exposed to a psychosocial stressor, the Trier Social Stress Test (TSST) and a control condition (Placebo (P-)TSST) in randomized order. Salivary cortisol, alpha amylase (sAA) and blood pressure were measured in response to stress. Subsequently, we examined free recall of a previously learned word list, autobiographical memory, and working memory.Results: We found a stress*time*group interaction effect for the cortisol response and for sAA to stress, which is mainly triggered by a slightly different increase in cortisol between groups from pre to post TSST. Furthermore, BPD patients showed a less pronounced increase in diastolic blood pressure compared to HC after stress. There was no effect of stress on memory performance in any tests, either in healthy controls or in patients with BPD.Conclusion: Our results suggest a slightly blunted response of the HPA axis and the sympathetic nervous system to stress in BPD compared to healthy women. In contrast to hydrocortisone administration, psychosocial stress did not improve memory retrieval in BPD patients. This might be explained by lower cortisol concentrations and parallel increases in norepinephrine and negative affect after stress.