Alerted default mode: functional connectivity changes in the aftermath of social stress

Abstract

Stress affects the brain at a network level: the salience network is supposedly upregulated, while at the same time the executive control network is downregulated. While theoretically described, the effects in the aftermath of stress have thus far not been tested empirically. Here, we compared for the first time resting-state functional connectivity in a large sample of healthy volunteers before and after a mild social stressor. Following the theoretical prediction, we focused on connectivity of the salience network (SN), the executive control network (ECN) and the default mode network (DMN). The DMN exhibited increased resting-state functional connectivity following the cyberball task to the key nodes of the SN, namely the dorsal anterior cingulate cortex (dACC) and the anterior insula, as well as sensorimotor regions and higher-order visual areas. We conclude that this increased connectivity of the DMN with key nodes of the SN and regions responsible for preparatory motor activity and visual motion processing indicates a shift towards an ‘alerted default mode’ in the aftermath of stress. This brain response may be triggered or aggravated by (social) stress induced by the cyberball task, enabling individuals to better reorient attention, detect salient external stimuli, and deal with the emotional and affective consequences of stress.

Multivariate associative patterns between the gut microbiota and large-scale brain network connectivity

“…For component 7, the spatial patterns of association were similar to results showing an alerted state of the DMN after social stress induction (15). In data using a similar paradigm, Bifidobacterium longum modulated activity in similar regions that were influenced by social stress and also in the hippocampus, a region that is part of the DMN (7).…”

“…Component 7 was associated to variability in the DMN again and to roughly 25% of the microbiota. The spatial pattern of betweensubject variation could be interpreted as elevated connectivity of the DMN to parts of the so-called salience network (such as dorsal anterior cingulate cortex (dorsal ACC) and ventrolateral prefrontal cortex (VLPFC)), which has in previous literature been associated with effects of elevated stress on DMN resting state connectivity (15,16). Ruminocuccus_2 was more abundant and Blautia was less abundant in individuals that showed this elevated connectivity pattern of DMN to dorsal ACC and VPLFC.…”

“…We used this selection in previous work to investigate the impact of fasting on functional connectivity in rest (14). We limited our study to a set of four networks of interest (the lateralized fronto-parietal (left/right) attention networks, FPN; the executive control network, ECN; and the default mode network, DMN) due to their importance in the neuroimaging field, their comparatively clear and cognitive functional profile and their importance in mental disease or previous microbiome research (10,11,(14)(15)(16).…”

Medial prefrontal decoupling from the default mode network benefits memory

“…Modulation of DMN connectivity with other networks during goal-directed cognition (Spreng and Grady, 32 2010), after and during stress induction (Clemens et al, 2017;Young et al, 2017). Recently it has been 33…”

Dynamic changes in thalamic connectivity following stress and its association with future depression severity

“…Studies examining stress‐induced neural responses and recovery patterns through post‐stress resting‐state functional magnetic resonance imaging (fMRI) scans are summarized in Table . Overall, the intra‐ and inter‐network functional connectivity (FC) of four core networks have been frequently reported altered after acute stress, including the default mode network (DMN), which is related to internally directed self‐referential thought and includes the posterior cingulate cortex (PCC; Clemens et al, ; Dimitrov et al, ; Quaedflieg et al, ; Vaisvaser et al, ; Zhang, Hashemi, et al, ; Zhang, Huettel, Mullette‐Gillman, Guo, & Wang, ); the salience network (SN), which detects bottom‐up salient events and reallocates the attention resources and includes the anterior insula and the dorsal anterior cingulate cortex (Clemens et al, ; van Marle, Hermans, Qin, & Fernandez, ; Zhang, Hashemi, et al, ; Zhang, Huettel, et al, ); the executive control network (ECN), which is mainly involved in executive function and includes the dorsolateral prefrontal cortex (dlPFC) and intraparietal lobe (IPL; Vaisvaser et al, ; Zhang, Huettel, et al, ); and the limbic system, which processes emotion information and directs it to the frontal cortex for decision‐making and includes the amygdala and the thalamus (Dimitrov et al, ; van Marle et al, ; Maron‐Katz, Vaisvaser, Lin, Hendler, & Shamir, ; Quaedflieg et al, ; Vaisvaser et al, ; Zhang, Huettel, et al, ). However, the main findings of these studies are quite divergent.…”