Longitudinal hippocampal circuit change differentiates persistence and remission of pediatric posttraumatic stress...

Previous studies have identified functional brain abnormalities in pediatric posttraumatic stress disorder (pPTSD) suggesting altered frontoparietal-subcortical function during emotion processing. However, little is known about how the brain functionally changes over time in recovery versus the persistence of pPTSD.

This longitudinal study recruited 23 youth with PTSD and 28 typically developing (TD) youth (ages: 8.07-17.99). Within the PTSD group, nine remitted by the 1-year follow-up (Remit) while the remaining 14 persisted (PTSD). At each visit, youth completed an emotional processing task in which they viewed threat and neutral images during functional magnetic resonance imaging (fMRI). Voxelwise activation analyses using linear mixed-effects regression were conducted using a group (TD, Remit, PTSD) by time (baseline, follow-up) by valence (threat, neutral) design. Based on activation findings, a subsequent analysis of hippocampal functional connectivity was performed using a similar model.

PTSD youth showed significantly increasing hippocampal activation to threatening images compared to TD youth, while the Remit group showed more similar patterns to TD youth. Subsequent hippocampal functional connectivity analyses reveal the Remit group showed increasing functional connectivity between the hippocampus and visual cortex (V4) while viewing threat stimuli.

These findings represent one of the first preliminary reports of functional brain substrates of persistence and remission in pPTSD. Notably, increased hippocampal activation to threat and decreased connectivity in the hippocampal-V4 network over time may contribute to persistence in pPTSD. These findings suggest potential biomarkers that could be utilized to advance the treatment of pediatric PTSD.