1078 DAILY MORNING BLUE LIGHT EXPOSURE LEADS TO CHANGES IN FUNCTIONAL BRAIN RESPONSES DURING EMOTIONAL ANTICIPATION IN INDIVIDUALS WITH PTSD

Abstract

Introduction: Some of the most common symptoms of post-traumatic stress disorder (PTSD) are sleep difficulties. Morning blue light exposure (BLE) has been used as a way to improve sleep and advance the circadian rhythm. The present study assessed whether six weeks of daily morning BLE can reduce PTSD symptom severity as a result of improved sleep, and affect functional brain responses when anticipating aversive emotional stimuli. Methods: Fourteen healthy adults (50% female) with a clinical diagnosis of PTSD (according to the Structured Clinical Interview for DSM-5) were randomly assigned to receive either six weeks of morning BLE (active condition, n=9) or amber light (placebo condition, n=5) for 30 minutes each day. Before and after the intervention, participants completed the Clinician Administered PTSD Scale for DSM-5 (CAPS-5) and underwent functional magnetic resonance imaging (fMRI) at 3T while completing an emotional anticipation task. Neuroimaging data were preprocessed and analyzed with SPM12 using standard algorithms. Standard regions of interest (ROIs) were placed bilaterally at the insula, amygdala, and medial prefrontal cortex. Results: While there was no difference in CAPS-5 symptom scores from pre- to post-light exposure between the two groups (F(1,12)=.09, p=.78), participants in the BLE group showed a significant increase in activation within the right medial frontal gyrus (22 voxels) and a decrease in activation within the right insula (10 voxels) when anticipating negative versus positive stimuli (p=.005, uncorrected). Conclusion: While we found no evidence for a reduction in PTSD symptoms due to daily morning BLE, these preliminary results suggest that daily BLE may alter responses in brain regions linked to emotion regulation. However, this was a preliminary study and future work with larger sample sizes will examine the possibility that these neuronal changes correspond to individuals’ behavioral responses when having to regulate emotions, as well as improved PTSD symptoms and sleep quality. Support (If Any): This study was supported by a USAMRAA grant.