Decoding Neural Threat Representations Using Shock Prediction Modelling in Women with PTSD Undergoing an Exposure Therapy Task

Poster Session B - Sunday, April 14, 2024, 8:00 – 10:00 am EDT, Sheraton Hall ABC

Kierra Morris¹ (kierra.morris@austin.utexas.edu), Josh Cisler²; ¹University of Texas at Austin Dell Medical School

Multivariate pattern analysis (MVPA) with support vector machines (SVM) has previously been utilized to decode distributed neural representations unique to threat presentation (i.e., electric shock) and demonstrate that those threat representations reactivate during approach-avoidance decision-making and predict decisions to avoid (Moughrabi et al., 2022). Here, we extended shock prediction modelling to test the hypothesis that traumatic memory recall reinstates neural representations of threat in individuals with posttraumatic stress disorder (PTSD). Women between the ages of 21-50 years old (N = 40) diagnosed with PTSD created personalized traumatic memory and neutral memory narratives. Participants then completed an analogue exposure therapy task, in which they read and listened to these narratives while undergoing fMRI, with four repetitions to each memory narrative. A threat decoder was trained on a separate dataset of participants completing an approach-avoidance task with an electric shock threat stimulus. This threat decoder was then applied to the voxel activity during the trauma vs neutral narratives, allowing us to test whether trauma memory recall engages neural representations of threat. When this decoder was trained within a specific anterior insula/inferior frontal gyrus network, resulting threat predictions were significantly higher for trauma compared to neutral narratives, t(1560) = 3.3, p< .001. When the threat decoder was trained on all grey matter voxels, there was less robust evidence for greater threat predictions in trauma vs neutral narratives, t(1560) =2.04, p = 0.045 . These findings shed light on the neural mechanisms underlying exposure therapy, offering novel insights to improving PTSD treatment strategies.

Topic Area: EMOTION & SOCIAL: Emotional responding