Re-experiencing trauma: Occipital lobe resting-state functional connectivity in posttraumatic stress disorder.

Re-experiencing symptoms in posttraumatic stress disorder (PTSD) often involve vivid visual imagery, yet occipital resting-state functional connectivity (rsFC) remains understudied, particularly in women exposed to interpersonal violence. Clarifying these neural mechanisms may advance understanding of sensory and contextual processing disturbances that contribute to intrusive memories. Notably, occipital rsFC has not been evaluated in relation to re-experiencing using the Posttraumatic Stress Diagnostic Scale (PDS), a validated self-report measure that supports fine-grained symptom-level analyses. Sixty-three participants meeting DSM-IV criteria for PTSD completed clinical assessments and resting-state fMRI. PTSD severity was measured with the Clinician-Administered PTSD Scale (CAPS-IV) and the PDS. We conducted seed-based voxelwise rsFC analyses using bilateral visual cortex seeds (V1, V2, V3) and tested associations with re-experiencing symptoms. Greater V3-left cerebellar connectivity was positively associated with PDS re-experiencing subscores (t(61)=5.32, pFWE < .05). Item-level analyses suggested this effect was driven by endorsements of nightmares (t(61)=4.18, pFWE < .05) and physiological reactivity (t(61)=4.77, pFWE < .05). Increased V3-cerebellar connectivity may reflect heightened coupling between visual and sensorimotor/regulatory systems supporting PTSD-related re-experiencing. These interactions may relate more specifically to re experiencing symptoms than to global PTSD severity, suggesting a potential symptom targeted neural marker in trauma-exposed females.