Poster Session D, Monday, March 25, 8:00 – 10:00 am, Pacific Concourse
Global Functional Network Modularity Facilitates Responding in Threat-Valenced Spatial Cueing
Marisa Ross1, Josh Cisler1; 1University of Wisconsin-Madison
Preferential orienting to threatening stimuli is a common phenotype of posttraumatic stress disorder (PTSD) and is potentially mediated by functional brain organization. In fact, research suggests that increased brain network modularity (Q), a metric of brain network integration and segregation, may facilitate orienting to basic cues, which may be disadvantageous in PTSD. This study investigated the interaction of neural network organization with spatial orienting in the context of threatening images. Here, 72 subjects (61 with PTSD, 11 healthy controls) underwent resting-state functional MRI (rs-fMRI) and completed a version of the Posner spatial cueing task (SCT) where the target was preceded by a threatening- or neutral-valenced image. rs-fMRI data were analyzed using a graph-network approach, where modularity was maximized using Louvain community detection. SCT data were modeled using a mixed linear effects model to gauge the effects of Q, PTSD diagnosis, validity and valence of the cue on reaction times during the task. We found a validity x Q x group interaction, which indicated quicker reaction times on incongruent trials for women with more globally modular brains. Interestingly, this effect appears to be driven by the control group, indicating a facilitating effect of modularity in healthy women that is not present in the PTSD group. These results suggest a mechanism for facilitation of spatial orienting that is present in healthy adults but with a less clear function in PTSD. This finding suggests a need for further exploration of the effect of brain network modularity in PTSD populations.
Topic Area: EXECUTIVE PROCESSES: Goal maintenance & switching