title: Neural traces of stress: cortisol related sustained enhancement of amygdala-hippocampal functional connectivity.
abstract: Stressful experiences modulate neuro-circuitry function, and the temporal trajectory of these alterations, elapsing from early disturbances to late recovery, heavily influences resilience and vulnerability to stress. Such effects of stress may depend on processes that are engaged during resting-state, through active recollection of past experiences and anticipation of future events, all known to involve the default mode network (DMN). By inducing social stress and acquiring resting-state functional magnetic resonance imaging (fMRI) before stress, immediately following it, and 2 h later, we expanded the time-window for examining the trajectory of the stress response. Throughout the study repeated cortisol samplings and self-reports of stress levels were obtained from 51 healthy young males. Post-stress alterations were investigated by whole brain resting-state functional connectivity (rsFC) of two central hubs of the DMN: the posterior cingulate cortex (PCC) and hippocampus. Results indicate a 'recovery' pattern of DMN connectivity, in which all alterations, ascribed to the intervening stress, returned to pre-stress levels. The only exception to this pattern was a stress-induced rise in amygdala-hippocampal connectivity, which was sustained for as long as 2 h following stress induction. Furthermore, this sustained enhancement of limbic connectivity was inversely correlated to individual stress-induced cortisol responsiveness (AUCi) and characterized only the group lacking such increased cortisol (i.e., non-responders). Our observations provide evidence of a prolonged post-stress response profile, characterized by both the comprehensive balance of most DMN functional connections and the distinct time and cortisol dependent ascent of intra-limbic connectivity. These novel insights into neuro-endocrine relations are another milestone in the ongoing search for individual markers in stress-related psychopathologies.
authors.affiliation: Functional Brain Center, Wohl Institute for Advanced Imaging, Sourasky Medical Center Tel-Aviv, Israel ; Sackler Faculty of Medicine, Tel Aviv University Tel Aviv, Israel ; Sagol School of Neuroscience, Tel Aviv University Tel Aviv, Israel.
authors.forename: Sharon
authors.initials: S
authors.lastname: Vaisvaser
authors.forename: Tamar
authors.initials: T
authors.lastname: Lin
authors.forename: Roee
authors.initials: R
authors.lastname: Admon
authors.forename: Ilana
authors.initials: I
authors.lastname: Podlipsky
authors.forename: Yona
authors.initials: Y
authors.lastname: Greenman
authors.forename: Naftali
authors.initials: N
authors.lastname: Stern
authors.forename: Eyal
authors.initials: E
authors.lastname: Fruchter
authors.forename: Ilan
authors.initials: I
authors.lastname: Wald
authors.forename: Daniel S
authors.initials: DS
authors.lastname: Pine
authors.forename: Ricardo
authors.initials: R
authors.lastname: Tarrasch
authors.forename: Yair
authors.initials: Y
authors.lastname: Bar-Haim
authors.forename: Talma
authors.initials: T
authors.lastname: Hendler
keywords: default-mode network; fMRI; limbic connectivity; recovery; resting-state functional connectivity