Psychiatry · 2 h ago
Posterior hippocampal glutamate marker linked to trauma reexperiencing symptoms
A study of 121 trauma-exposed adults with frequent intrusive memories examined hippocampal glutamate-to-N-acetyl aspartate ratios and brain connectivity. Higher ratios in the posterior, but not anterior, hippocampus were associated with more severe reexperiencing symptoms and stronger connectivity with visual cortex.
- Higher posterior hippocampal Glu/NAA tracked with symptom severity.
- No corresponding association was found in the anterior hippocampus.
- Posterior hippocampus–visual cortex connectivity was also associated with symptoms.
- Observational imaging findings do not establish causation or treatment benefit.
In this observational imaging study, 121 community-recruited adults aged 18–65 years who reported at least two trauma-related intrusive memories per week completed the Clinician-Administered PTSD Scale for DSM-5, magnetic resonance spectroscopy and resting-state functional MRI. The researchers assessed glutamate-to-N-acetyl aspartate (Glu/NAA) ratios in the anterior and posterior hippocampus and examined their associations with symptom severity and functional connectivity.
Greater reexperiencing symptom severity was associated with higher Glu/NAA in the posterior hippocampus, but not the anterior hippocampus. Higher posterior hippocampal Glu/NAA was also associated with stronger connectivity between that region and the visual cortex; stronger connectivity was, in turn, associated with more severe symptoms. The connectivity finding statistically accounted for shared variance between the posterior hippocampal marker and symptom severity.
The findings extend prior work by identifying a regional association consistent with sensory-rich memory involvement in trauma reexperiencing. They are correlational and do not establish that glutamate dysfunction causes symptoms or that modifying this pathway improves them. The results identify possible research targets, not a basis for changing clinical care; some imaging data were unavailable or excluded because of technical issues or quality concerns.
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Molecular Psychiatry: Multimodal associations between posterior hippocampus glutamate metabolism, visual cortex connectivity, and intrusive trauma reexperiencing symptoms ↗This is an automated AI-condensed summary that has not yet been reviewed by an editor. Always consult the full item at the original source.