Naturalight: A controlled illuminated environment to study light exposure impact on behavior and cognition in freely moving rats

Abstract

In humans, scientific studies have shown that the increased use of screens at night and prolonged exposure to artificial light, particularly blue light, can significantly disrupt the organization of sleep-wake cycles and the functions that depend on them like memory. In rodents, moderate and even weak exposures to light have been shown to have various and either detrimental or beneficial effects on circadian rhythms, behavior, cognition. Yet, scattered and sometimes opposite effects are reported in the literature, which is largely attributed to differences in experimental conditions, especially on the definition and evaluation of the actual dose of light received. To address this issue, we have built an enclosure with controlled and characterized illumination. It can be used as a standalone experimental environment or eventually connected to naturalistic environment where several animals live constantly and interact freely within several housing modules, including the controlled illumination one.