A Network-Based Neurobiological Model of PTSD: Evidence From Structural and Functional Neuroimaging Studies

Abstract

Purpose of Review Although a fine-grained understanding of the neurobiology of posttraumatic stress disorder (PTSD) is yet to be elucidated, the last two decades have seen a rapid growth in the study of PTSD using neuroimaging techniques. The current review summarizes important findings from functional and structural neuroimaging studies of PTSD, by primarily focusing on their relevance towards an emerging network-based neurobiological model of the disorder. Recent Findings PTSD may be characterized by a weakly connected and hypoactive default mode network (DMN) and central executive network (CEN), that are putatively destabilized by an overactive and hyperconnected salience network (SN) – which appears to have a low threshold for perceived saliency, and inefficient DMN-CEN modulation. Summary There is considerable evidence for large-scale functional and structural network dysfunction in PTSD. Nevertheless, several limitations and gaps in the literature need to be addressed in future research.

Altered White Matter Diffusivity of the Cingulum Angular Bundle in Posttraumatic Stress Disorder

“…Moreover, associations have been reported between CAB integrity and functioning in episodic memory, decision-making, and executive control [42,43]. The CAB has also been shown to directly connect the posterior cingulate cortex and the subiculum of the hippocampus [44], both of which are critical nodes in the default mode network shown to be altered in PTSD [1,45]. The CAB connects the hippocampus and other regions of the medial temporal lobe with the posterior cingulate [43], an area that has been shown to exhibit alterations of gray matter integrity (thinning) in this group of participants [30].…”

“…Despite decades of psychiatric research, a comprehensive understanding of the network disruptions [1] predisposing and underlying posttraumatic stress disorder (PTSD) is still emerging [2,3]. While the majority of neuroimaging investigations have focused on structural [4] and functional [5] aspects of PTSD, there is a growing body of literature regarding white matter integrity related to the disorder.…”

Trauma, PTSD, and the Developing Brain

“…For an in depth discussion of this topic in adult PTSD, I refer readers elsewhere in this special issue [17]. Briefly, numerous studies have identified a set of core, functionally connected networks in the brain.…”

“…In addition to the frontolimbic model, recent work also implicates dysfunction in larger scale brain networks in adult PTSD involved in salience detection, self-referential thought, and executive control. A more in depth discussion of these network abnormalities can found be found elsewhere in this special issue [17], though I briefly discuss relevant findings in pediatric PTSD later in this article.…”

Evaluating web-based cognitive-affective remediation in recent trauma survivors: study rationale and protocol

“…Beyond the fronto-limbic circuitry, aberrations between and within (Sripada et al, 2012) the default mode network (DMN), salience network (SN), and the central executive network (CEN) were demonstrated in PTSD. The DMN and CEN were found to be weakly interconnected and hypoactive, hypothetically destabilized by an overactive and hyper-connected SN and a low saliency perception threshold, along with inefficient DMN-CEN modulation (Akiki, Averill, & Abdallah, 2017). Abnormalities within the CEN may underlie some of the cognitive, executive, and emotional regulatory dysfunctions in PTSD (Lanius, Frewen, Tursich, Jetly, & McKinnon, 2015).…”