0079 Blue Light Exposure Enhances Neural Efficiency of the Task Positive Network During a Cognitive Interference Task

Abstract

Introduction: Light exposure has powerful effects on the circadian timing of sleep and wake, primarily through the regulation of the secretion of melatonin. However, it is becoming clear that light has additional alerting effects beyond its primary effect on the circadian system. Exposure to light, particularly blue-wavelength light, has been shown to acutely increase brain activation, alertness, and some elementary aspects of cognitive performance such as working memory and emotional anticipation during the day. Whether blue light exposure can have longer-lasting effects on brain activation and performance during more complex cognitive control tasks up to 30-minutes after light cessation is unknown. Methods: In a sample of 30 healthy adults, we examined the effects of a single 30-minute exposure to either blue (n=14) or amber placebo (n=16) light on subsequent brain activation and performance during the Multi-Source Interference Task (MSIT) measured a half-hour after light cessation using functional magnetic resonance imaging. Mean activation in all regions showing increased taskrelated activation (i.e., Task Positive Network; TPN) and regions showing decreased activation (i.e., Default Mode Network; DMN) at p