Eyes regulate sleep cycles

CHARLOTTESVILLE, Va., Aug. 16 (UPI) -- U.S. biologists said they've discovered the switching mechanism in the eye that helps the brain regulate activity and rest cycles in mammals.

Researchers said light receptor cells in the eye are key to setting the rhythms of the brain's primary timekeeper, the suprachiasmatic nuclei.

Lead author Susan Doyle of the University of Virginia said the finding could lead to new treatments for sleep disorders.

"Perhaps even eye drops that would target neural pathways to the brain's central timekeeper," Doyle said Friday in a release.

Researchers were able to reverse the sleep/wake cycle of mice by reducing the intensity of light given to normal mice and creating a new line of mutated mice with reduced light sensitivity, the university said.

The research is published in the journal of the Proceedings of the National Academy of Sciences.