Aberrant Resting-State Brain Activity in Posttraumatic Stress Disorder: A Meta-Analysis and Systematic Review

Abstract

Combined, these altered resting-state connectivity and activity patterns could represent neurobiological correlates of increased salience processing and hypervigilance (SN), at the cost of awareness of internal thoughts and autobiographical memory (DMN) in PTSD. However, several discrepancies between findings of the meta-analysis and systematic review were observed, stressing the need for future studies on resting-state abnormalities in PTSD patients.

Mindfulness-based treatments for posttraumatic stress disorder: a review of the treatment literature and neurobiological evidence

“…Two recent meta-analyses have highlighted reduced activation in areas of the brain associated with the DMN, including the mPFC, the PCC and posterior inferior parietal lobule, and the parahippocampal gyrus. 61,92 Reduced functional connectivity between DMN nodes, including the PCC, posterior hippocampus and vmPFC, has also been reported 92 and has been associated with PTSD symptom severity 93,94 (Fig. 2).…”

“…Such changes in SN nodes are posited to underlie hyperarousal symptoms in patients with PTSD and overall dominance of the threat sensitivity circuit. 92 In addition, altered functional connectivity has been consistently noted between nodes of the DMN and SN, where increased connectivity has been reported between the ventral ACC (vACC; generally considered to be part of the mPFC) and PCC with the insula 94,97 ( Fig. 2).…”

“…Reduced DMN functional connectivity is thought to underlie impairments in self-referential processes, autobiographical memory and altered sense of self seen in patients with PTSD. 75,92 By contrast, increased resting-state functional connectivity among nodes of the SN, such as the amygdala and AI, 92,[94][95][96] as well as increased activation in SN regions at rest, including the AI, dACC and amygdala, 61,92 have been reported consistently among individuals with PTSD. Such changes in SN nodes are posited to underlie hyperarousal symptoms in patients with PTSD and overall dominance of the threat sensitivity circuit.…”

“…93 Overall, patterns of increased connectivity between nodes of the SN and DMN are posited to reflect increased threat processing and hypervigilance at the expense of appropriate self-referential processing. 92 Activity and connectivity of the CEN is also disrupted in individuals with PTSD, with meta-analytic findings pointing to reduced activity in the dlPFC. 61 Interestingly, one study reported inappropriate activation of the DMN during a working memory task among patients with PTSD that contrasted with appropriate activation of the CEN among controls, suggesting an inability to recruit task-positive networks in individuals with PTSD.…”

“…Specifically, hyperconnectivity between DMN and SN nodes among individuals with PTSD has been cited as a potential cause of increased hyperreactivity and threat processing at the expense of effective selfreferential processing. 92 Similarly, increased connectivity between the DMN and CEN has been associated with dissociative symptoms. 98 Critically, a recent study reported that increased scores on measures of mindfulness following 2 weeks of self-guided attention to breath training among healthy controls was associated with reduced resting state connectivity between the SN (anterior insula) and the DMN.…”