Your Health 11-14-12 Depression and light at night

Want to feel happier as the evening sets in and your day comes to a close?

New research suggest that when the sun goes down, you might end up happier and better able to learn new things, if you turn down all the lights -- even your computer screen.

Unfortunately, the study subjects were mice.{} But, researchers at Johns Hopkins University, in Baltimore say the findings could apply to people.

They say mice share the same set of special light-activated cells in their eyes that humans have.{} Those cells are known as ipRGCs.

Researchers say those cells, called intrinsically photosensitive retinal ganglion cells, are stimulated by bright light, which affects the brain's mood, memory and learning centers.

The study found that chronic exposure to bright light at night elevates cortisol, a stress hormone that can cause depression and reduce thinking function.

The research appears in the online journal, Nature.