By Madison DeWitt

Faculty Mentor: Dr. Parrish Waters

Abstract

Extended exposure to artificial blue light, such as the light from computer screens, can disrupt the sleep cycle, perhaps by disrupting daily cycles of the hormone cortisol; both of these effects can diminish behavioral and somatic health. This experiment investigated how blue light affects cortisol levels, anxiety levels, and activity levels using a laboratory mouse model. We exposed mice to dim light from a computer screen (iPad 2) throughout the dark phase to simulate blue light exposure. We also maintained a group of mice who experienced red light, a light source that does not seem to disrupt these variables. We kept a third group that were exposed to no light during the 12-hour dark phase that served as an additional control group. All cages were brightly lit with white light from 9AM to 9PM, following a typical 12:12 light cycle. After 4 weeks we measured anxiety and collected blood plasma to measure levels of the stress hormone corticosterone. I predicted that our data would demonstrate that exposure to blue light disrupts sleep patterns, activity levels, and mood, and would show that increased levels of the stress glucocorticoids mediate these behavioral changes. Although we have not collected results as of yet, we will have results prior to the symposium!