Stress Impact on Resting State Brain Networks

Abstract

Resting state brain networks (RSNs) are spatially distributed large-scale networks, evidenced by resting state functional magnetic resonance imaging (fMRI) studies. Importantly, RSNs are implicated in several relevant brain functions and present abnormal functional patterns in many neuropsychiatric disorders, for which stress exposure is an established risk factor. Yet, so far, little is known about the effect of stress in the architecture of RSNs, both in resting state conditions or during shift to task performance. Herein we assessed the architecture of the RSNs using functional magnetic resonance imaging (fMRI) in a cohort of participants exposed to prolonged stress (participants that had just finished their long period of preparation for the medical residence selection exam), and respective gender- and age-matched controls (medical students under normal academic activities). Analysis focused on the pattern of activity in resting state conditions and after deactivation. A volumetric estimation of the RSNs was also performed. Data shows that stressed participants displayed greater activation of the default mode (DMN), dorsal attention (DAN), ventral attention (VAN), sensorimotor (SMN), and primary visual (VN) networks than controls. Importantly, stressed participants also evidenced impairments in the deactivation of resting state-networks when compared to controls. These functional changes are paralleled by a constriction of the DMN that is in line with the pattern of brain atrophy observed after stress exposure. These results reveal that stress impacts on activation-deactivation pattern of RSNs, a finding that may underlie stress-induced changes in several dimensions of brain activity.

Reduced default mode network connectivity following combat trauma

“…Further investigation of chronic stress, including early life stress, on the DMN will do much to enrich our understanding of changes to large-scale intrinsic connectivity networks. Interestingly, although there are some studies that suggests stress decreases connectivity in the DMN, an animal study [28] and a study of medical students [29] found that exposure to prolonged stress was related to increased DMN activity. Of note, Kennis et al [30] recently showed reduced resting state connectivity between the perigenual ACC (as part of the mPFC and DMN) and the superior medial frontal gyrus and medial temporal gyrus in traumatizes subjects with and without PTSD, relative to controls, consistent with our findings.…”

Relationship Between Alzheimer Disease–Like Pattern of 18F-FDG and Fasting Plasma Glucose Levels in Cognitively Normal Volunteers

“…These lines of evidence, combined with our current observations, support an explanation that increased fasting PG and insulin levels (i.e., greater insulin resistance) causes a reduction of functional connectivity in the DMN, leading to reduced uptake of 18 F-FDG (i.e., glucose hypometabolism), especially in the precuneus. Furthermore, prolonged stress can affect the pattern of activity in the DMN (27).…”

Cortical Thickness of Native Tibetans in the Qinghai-Tibetan Plateau

“…Previous multimodal neuroimaging studies have shed light on this functionstructure association, underlining cognition, aging, disease, and behavior. 49 The changed activity within the DMN in response to chronic stress exposure has been found in humans 50 and animals. 51 The impairment of cortical structures in HA Tibetans is likely to reflect the stress-induced atrophic effects in cortical regions.…”