Brain Network Dynamics Following Induced Acute Stress: A Neural Marker of Psychological Vulnerability to Real-Life Chronic Stress

Abstract Stress engages multiple neurobiological modifications and a failure to regulate these may lead to chronic psychiatric problems. Despite considerable research, it remains unclear how neural alterations of acute stress reflect the ability to cope with chronic stress. The current longitudinal study examined the whole-brain network dynamics following induced acute stress and its prediction of vulnerability to real-life chronic stress. 60 military pre-deployment soldiers (all male) underwent a lab-induced stress task during which resting fMRI was acquired before stress, after stress, and at recovery (90 minutes later). Subjective stress was repeatedly measured during the experiment. Depression and post-traumatic stress symptoms were also evaluated, as well as a year later during military deployment. A time-varying analysis was applied to characterize the dominant activity of different states as they change over time. Findings reveal that, from acute stress to recovery, the frontoparietal and subcortical states decrease in dominance in favor of the default mode network, sensorimotor, and visual states. Moreover, rebalancing of the frontoparietal state activity is related to successful psychological recovery. Lastly, elevated activity of the frontoparietal state is related to vulnerability to chronic stress as indicated by depressive symptoms. In conclusion, our study demonstrates that recovery from acute stress involves the downregulation of cognitive-emotional functioning states (i.e., the frontoparietal and the subcortical states), and an enhancement of self-awareness and sensory-perception states. Moreover, the high dominance of the frontoparietal state is suggested as a potential neural marker of psychological vulnerability to chronic stress.