Differences in Neural Recovery From Acute Stress Between Cortisol Responders and Non-responders

Description: Adaptive recovery from a stressor fosters resilience. So far, however, few studies have examined brain functional connectivity in the aftermath of stress, while divergent results were mostly found. Focusing on the immediate recovery from psychosocial stress, the current study compared amygdala resting-state functional connectivity (RSFC) before and immediately after psychosocial stress between cortisol responders and non-responders. Differences between groups were expected for amygdala RSFC with regions involved in down-regulation of the physiological stress response, emotion regulation, and memory consolidation. Eighty-six healthy participants (36 males/50 females) underwent a social stress paradigm inside the MRI scanner. Before and immediately after stress, resting-state (RS) fMRI scans were acquired to determine amygdala RSFC using a seed-based correlation approach. Changes in connectivity from pre- to post-stress were then compared between cortisol responders and non-responders. Responders showed a typical cortisol increase to the stress task, reported higher negative affect during stress, and had decreased heart rate variability in response to stress compared to non-responders. As males were more likely to show a cortisol increase to the stress task than females, RS analyses were conducted for both sexes separately. Whereas there was no difference in RSFC between female responders and non-responders from pre- to post-stress, male non-responders showed an increase in FC between bilateral amygdala and posterior cingulate cortex (PCC) and precuneus (p < .05, whole-brain FWE-corrected). The increased coupling of the amygdala with the PCC/precuneus, a core component of the default mode network (DMN), might indicate an increased engagement of the amygdala within the DMN directly after stress in non-responders. Although this study was carried out in healthy participants, and the results likely reflect normal variations in the neural response to stress, understanding the mechanisms that underlie these variations could prove beneficial in revealing neural markers that promote resilience to stress-related disorders.

Related article: http://doi.org/10.3389/fpsyt.2018.00631