Intrinsic functional connectivity of right dorsolateral prefrontal cortex and hippocampus subregions relates to emotional and sensory-perceptual properties of intrusive trauma memories.

Background: Trauma-related intrusive memories (TR-IMs) are core symptoms of posttraumatic stress disorder (PTSD). Prior research links reexperiencing symptoms with resting-state functional coupling between the right dorsolateral prefrontal cortex (dlPFC) and right hippocampus. However, prior work has not examined whether this negative coupling relates to TR-IMs, nor differentiated between the anterior and posterior hippocampus (aHPC/pHPC). This study examined relationships of TR-IM frequency and properties with resting-state negative coupling between the right dlPFC and right aHPC/pHPC in symptomatic trauma-exposed individuals with TR-IMs.

Methods: Participants (N=109; 88 female) completed two weeks of ecological momentary assessments capturing TR-IM frequency and properties (intrusiveness, emotional intensity, vividness, visual properties, and reliving). Using resting-state functional magnetic resonance imaging, participant-specific 4-mm spheres were placed at the right dlPFC voxel most anticorrelated with the right aHPC and pHPC. Quasi-Poisson and linear mixed-effects models assessed relationships of TR-IM frequency and properties with right dlPFC-right aHPC and pHPC anticorrelation.

Results: TR-IM emotional intensity was positively associated with right dlPFC-aHPC connectivity, while vividness and visual properties correlated with right dlPFC-pHPC connectivity. These associations remained significant after controlling for PTSD symptom severity and time since trauma. No significant associations emerged between TR-IM frequency, intrusiveness, or reliving, and anticorrelation with either hippocampal subregion.

Conclusions: This study provides novel insights into the neural correlates of TR-IMs, highlighting the relevance of intrinsic negative coupling between the right dlPFC and aHPC/pHPC to their phenomenology. Further research on this circuit could advance understanding of component processes of trauma reexperiencing, a severe and treatment-refractory PTSD symptom.