Neuromodulation of the Hippocampus to Reduce Intrusive Re-Experiencing in PTSD: A Randomized Controlled Trial

Overview

The goal of this clinical trial is to learn if non-invasive neurostimulation of memory-related brain areas works to treat intrusive memory symptoms in adults patients with posttraumatic stress disorder (PTSD). It will also learn about the effect of this neuromodulation procedure on reorganization of memory-related brain networks. The main questions it aims to answer are: Does neuromodulation lower the number of times and the emotional severity participants intrusive memories? Does neuromodulation reduces the overall severity of PTSD? Researchers will compare neuromodulation targeting the hippocampus (a memory-related brain structure) to a control stimulation in an area not related to memory processes to see if hippocampus neuromodulation works to treat intrusive trauma memories and PTSD. Participants will: 1. Undergo magnetic resonance imaging (MRI) scans before and after neuromodulation to: a) determine a personalized neuromodulation target; and b) to measure changes in brain function from before to after treatment. 2. Receive hippocampus neuromodulation or a control neuromodulation once a week for 5 weeks. Keep a daily diary of their symptoms and the number of times they experience intrusive trauma memories.

Intrusive trauma memories are a hallmark of posttraumatic stress disorder (PTSD), and the least treatment responsive. Thus, revealing neurocognitive mechanisms associated with intrusive trauma memories has been indexed a priority. Prior work shows that targeting hippocampal circuitry modulates functional connectivity among distributed cortical-hippocampal network regions and alters memory performance in healthy participants. In the current clinical trial we test hypotheses on the clinical effects of such stimulation in a two-arms randomized controlled trial: Trauma memory reactivation + targeted hippocampal transcranial magnetic stimulation TMS (R-H-TMS) and Trauma memory reactivation + Control TMS (over the SMA; R-C-TMS). We will test a) Hippocampus seed-based connectivity patterns - revealing the impact of the targeted stimulation on extended memory brain networks; and b) frequency and severity of intrusive memory symptoms. The R-H-TMS vs. R-C-TMS contrast will speak to specificity of the noted effects to hippocampal stimulation.