Altered resting-state functional connectivity of the default mode and central executive networks following cognitive processing therapy for PTSD

Abstract

Psychotherapy research is increasingly targeting both psychological and neurobiological mechanisms of therapeutic change. This trend is evident in and applicable to post-traumatic stress disorder (PTSD) treatment research given the high nonresponse rate of individuals with PTSD who undergo cognitive-behavioral therapy (CBT). Functional connectivity analyses investigating disrupted brain networks across mental disorders have been employed to understand both mental disorder symptoms and therapeutic mechanisms. However, few studies have examined pre-post CBT brain changes in PTSD using functional connectivity analyses. The current study investigated a) whether brain networks commonly implicated in psychopathology (e.g., default mode network [DMN], central executive network [CEN], and salience network [SN]) changed following Cognitive Processing Therapy (CPT) for PTSD and b) whether change in these networks was associated with PTSD and/or transdiagnostic symptom change. Independent components analysis was implemented to investigate resting-state functional connectivity in DMN, CEN, and SN in 42 women with PTSD and 18 trauma-exposed controls (TEC). Results indicated decreased CEN-cerebellum connectivity in PTSD participants versus TEC prior to CPT and decreased DMN connectivity in PTSD participants after CPT. Additionally, DMN and SN connectivity was related to change in positive and negative affectivity, while exploratory analyses at a cluster threshold of pFDR < .10 indicated DMN and SN connectivity was also related to change in PTSD symptoms and rumination. These findings provide evidence for normalization of CEN connectivity with treatment and implicate the DMN and SN in clinical symptom change following CPT.

Keywords: Central executive network; Cognitive processing therapy; Default mode network; Functional connectivity; PTSD; Salience network.

Figure 1. Spatial Pattern of Network Components

Note. Component maps illustrate the spatial distribution for the three networks of interest from the independent component analysis. The two components with the highest correlations with the DMN, CEN, and SN templates are shown. For visualization purposes, component maps were thresholded at p-uncorrected < .001 and z > 1. All component maps are displayed on the MNI-152 template. DMN = default mode network; CEN = central executive network; SN = salience network.

Figure 2. DMN Connectivity Differentiating PTSD Treatment Completers at Time 2 from TEC

Note. Results show significant differences in DMN connectivity between PTSD and TEC participants at pFDR < .05. Findings are displayed on the MNI-152 template. DMN = default mode network; TEC = trauma-exposed controls.

Figure 3. Pre-Post DMN Connectivity Associated with Clinical Symptom Change

Note. Results reveal significant relationships between pre-post DMN connectivity and change in PTSD symptoms (red), positive affectivity (blue), and negative affectivity (green) at pFDR < .05 or pFDR < .10. Yellow represents overlap in PTSD symptom and negative affectivity clusters. Results are displayed on the MNI-152 template. DMN = default mode network.

Figure 4. Pre-Post SN Connectivity Associated with Clinical Symptom Change

Note. Results show significant relationships between pre-post SN connectivity and change in rumination (red) and positive affectivity (blue) at pFDR < .10. Results are displayed on the MNI-152 template. SN = salience network.