Effect of TMS on PTSD Biomarkers

Amygdala reactivity during fear processing were assessed by fMRI responses as participants viewed 15 blocks each of fearful face and neutral face stimuli, while amygdala reactivity was measured. The amygdala was separated in the right and left hemispheres.

fMRI measures the blood oxygen level-dependent response, a measure of how much more oxygenated blood there is in a certain brain region, which reflects activation of the brain region.

A regression model was used to determine the beta value as a measure of brain activity. Across voxels in each region (right amygdala, left amygdala), the beta value for response in the amygdala to Fearful faces and Neutral faces was extracted.

Change in skin conductance response to trauma cues pre- to post-treatment was assessed. The mobile skin conductance response was measured in microsiemens when participants described their worst trauma, followed by assessment of their symptoms. A numeric value estimating the skin conductance response was calculated by subtracting the baseline skin conductance reactivity from the reactivity during the trauma description.

Change in inhibition-related activation in the vmPFC was assessed by fMRI responses as participants viewed 15 blocks each of fearful face and neutral face stimuli. At the same time, reactivity in the ventromedial prefrontal cortex was measured. Across voxels in the ventromedial prefrontal cortex, a contrast estimate of responses to Fearful > Neutral faces was extracted.

This is being reported as a numeric value estimating inhibition-related brain activation (contrast estimate fear versus neutral)

Change in inhibition-related activation in the hippocampus was assessed by fMRI responses as participants viewed 15 blocks each of fearful face and neutral face stimuli, while hippocampal reactivity was measured.

The hippocampus was separated into the right and left hemispheres. Across voxels in each region (right hippocampus, left hippocampus), a contrast estimate of Fearful > Neutral faces was extracted.

Change in vmPFC-amygdala functional connectivity pre- to post-treatment was assessed. A numeric value estimating the correlation between the vmPFC and amygdala was measured.

Change in DLPFC-amygdala functional connectivity pre- to post-treatment was assessed. A numeric value estimating the correlation between the DLPFC and amygdala was measured.

Change in Fear-Potentiated Startle Responses to danger and safety cues pre- to post-treatment was assessed. An eye blink response was measured using electromyography with sensors placed near the eyes. Symbols were presented on a screen, one symbol followed by an airblast to the throat was the danger cue and a different symbol not followed by the airblast was the safety cue. The eye blink response in response to danger and safety cues was measured.

Change in discrimination between danger and safety cues pre- to post-treatment was assessed. An eye blink response was measured using electromyography with sensors placed near the eyes. Symbols were presented on a screen, with one symbol followed by an airblast to the throat serving as the danger cue, and a different symbol, not followed by the airblast, serving as the safety cue. The eye blink response in response to danger and safety cues was measured. The difference score for the eye blink response to danger and safety was calculated.

The severity of self-reported PTSD hyperarousal symptoms was assessed with the PCL-5, sub-cluster E. The PCL-5 asks participants to recall the worst stressful event that is currently bothering them the most. Keeping this event in mind, participants respond to 20 questions indicating how bothered they have been by PTSD symptoms. Responses are on a 5-point scale, where 0 = not bothered at all and 4 = extremely bothered. The 6 questions related to hyperarousal were used. Total raw scores range from 0 to 24, where higher scores indicate greater distress from PTSD hyperarousal symptoms.