Reduction of Trauma-induced Intrusions and Amygdala Hyperreactivity Via Non-invasive Brain Stimulation

Reduction of Trauma-induced Intrusions and Amygdala Hyperreactivity Via Non-invasive Brain Stimulation

The study will focus on the modulation of intrusive memories via functional magnetic resonance imaging (fMRI)-guided repetitive transcranial magnetic stimulation of the dorsolateral prefrontal cortex (dlPFC) directly after exposure to a traumatic video.

Traumatic experiences can lead to posttraumatic stress disorder (PTSD) with clinical manifestations including intrusions, avoidance behavior, and hyperarousal. Unlike most other psychological disorders, a PTSD diagnosis requires a clearly identifiable inciting event. As such, preventive interventions in recently traumatized individuals seem promising.

In this randomized, placebo-controlled study the investigators explore the potential of individualized transcranial magnetic stimulation (TMS) to reduce trauma-induced intrusive thoughts by altering functional connectivity between the dorsolateral prefrontal cortex (dlPFC) and amygdala. Subjects will undergo a functional magnetic resonance imaging (fMRI) session consisting of a resting state scan, an emotion recognition task and an anatomical scan at the beginning of the study (day 1). Resting state data will be used to determine individualized TMS targets for every subject, depending on functional connectivity between the dlPFC and amygdala. Subsequently, the analogue trauma model will be used to induce intrusions in healthy subjects. Subjects will be confronted with a video clip from the movie "Irreversible" and they will complete online questionnaires in the following three days to measure intrusive thoughts, trauma disclosure (i.e. duration of conversations about the aversive movie) and sleeping quality. Intermittent theta-burst stimulation (iTBS) will be administered directly after the video clip and on the following two days (day 2-4). Cognitive tasks will be applied before and after iTBS sessions to examine short-term effects of iTBS on a behavioral level. Finally, subjects will undergo a second fMRI session similar to the first one, to probe iTBS-induced changes in functional connectivity and emotional processing (day 5).

Inclusion Criteria:

• Healthy subjects

Exclusion Criteria:

• current psychiatric illness
• current psychiatric medication or psychotherapy
• past PTSD diagnosis
• MRI contraindication (e.g. metal in body, claustrophobia)
• pregnancy