title: 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.
authors.affiliation: Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Campus Gualtar, Braga, Portugal ; ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal ; Clinical Academic Center - Braga, Portugal.
authors.forename: José Miguel
authors.initials: JM
authors.lastname: Soares
authors.forename: Adriana
authors.initials: A
authors.lastname: Sampaio
authors.forename: Luís Miguel
authors.initials: LM
authors.lastname: Ferreira
authors.forename: Nadine Correia
authors.initials: NC
authors.lastname: Santos
authors.forename: Paulo
authors.initials: P
authors.lastname: Marques
authors.forename: Fernanda
authors.initials: F
authors.lastname: Marques
authors.forename: Joana Almeida
authors.initials: JA
authors.lastname: Palha
authors.forename: João José
authors.initials: JJ
authors.lastname: Cerqueira
authors.forename: Nuno
authors.initials: N
authors.lastname: Sousa
mesh_terms: D000328:Adult; D001921:Brain / Q000503:physiopathology*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000032:analysis; D008297:Male; D013315:Stress, Psychological; D055815:Young Adult
chemical_list: D006854:Hydrocortisone