Light at night negatively affects mood in diurnal primate-like tree shrews via a visual pathway related to the perihabenular nucleus

What is it about?

To better understand the potential health threats and underlying visual pathways of long-term light-at-night (LAN) exposure, we adopted a widely accepted diurnal animal model tree shrew (Tupaia belangeri chinensis), which is a close relative to primates, and evaluated the deleterious effects of long-term LAN exposure. We used an early-night LAN paradigm that was established in mice to examine behavioral and physiological consequences in adult male tree shrews. We found that 3-week LAN exposure significantly impaired the mood and long-term memory of tree shrews without affecting the general activity pattern.

Featured Image

Photo by HONG FENG on Unsplash

Photo by HONG FENG on Unsplash

Why is it important?

Long-term light-at-night (LAN) exposure poses a health threat to nocturnal lab animals. Whether diurnal animals suffer the same deleterious effect imposed by LAN and how it works are still open questions. Our study shows that tree shrew, a primate-like diurnal animal, presents impaired mood and cognitive functions upon 3-week LAN exposure. This effect is mediated by a conserved retina-perihabenular nucleus (pHb)-nucleus accumbens (NAc) pathway. Our findings constitute the basis for translational work aiming to prevent or treat mood disorders associated with excessive LAN