Regional Prefrontal Resting-State Functional Connectivity in Posttraumatic Stress Disorder

Abstract

Background: Prefrontal subregions, including the ventromedial prefrontal cortex (PFC), dorsomedial PFC, and dorsolateral PFC (DLPFC), are differentially implicated in the pathophysiology of posttraumatic stress disorder (PTSD), though few existing studies have examined subregional differences in resting-state functional connectivity (rsFC). We hypothesized that PTSD would involve weaker positive rsFC between ventromedial PFC, dorsomedial PFC, and other default mode network regions and increased negative rsFC between DLPFC and posterior default mode network regions. Additionally, we hypothesized that prefrontal regions exhibiting group differences in rsFC would be characterized by alterations in cortical thickness.

Methods: Participants included 36 healthy control subjects, 30 trauma-exposed control subjects, and 21 individuals with current DSM-IV PTSD resulting from community-acquired trauma. Participants completed the Clinician Administered PTSD Scale, questionnaires (Childhood Trauma Questionnaire, Adverse Childhood Events, Life Events Checklist, Beck Depression Inventory), structural neuroimaging, and resting-state functional magnetic resonance imaging. rsFC of DLPFC, ventromedial PFC, and dorsomedial PFC seeds was evaluated in SPM12 and CONN. Cortical thickness for regions with significant rsFC findings was assessed using FreeSurfer.

Results: Relative to both healthy control and trauma-exposed control subjects, individuals with PTSD showed increased negative rsFC between the DLPFC and a region of precuneus. This finding was associated with increased overall symptom severity but not with trauma load or childhood trauma exposure. Greater negative DLPFC-precuneus connectivity was associated with greater bilateral precuneus thickness.

Conclusions: Given participation of precuneus subregions in the central executive network, increased anticorrelation between right DLPFC and precuneus in this sample may reflect increased opposition between anterior and posterior central executive network hubs in PTSD.

Keywords: Cortical thickness; Functional connectivity; Posttraumatic stress disorder; Precuneus; Prefrontal cortex; Resting state.

Figure 1.

Region in precuneus with significant group difference in right DLPFC resting state functional connectivity. k = 212 voxels, p-FDR = 0.000064, peak coordinates = (+8, −72, +32).

Figure 2.

Group comparison of right DLPFC-precuneus rsFC values. Note: rsFC values in this graph are raw (not corrected for age and sex). Error bars: 95% confidence interval.

Figure 3.

Partial correlation of CAPS total symptom scores (left) and CAPS avoidance scores (right) with right DLPFC-precuneus rsFC in PTSD group, controlling for age and sex.