Sunlight Boosted Memory in Mice–Could It Do the Same for Humans?

The trick to a sharper memory? A walk in the sun, new science claims.

In small doses, UV light can trigger chemical processes that enhance memory and learning in mice, University of Science and Technology of China scientists found, and there’s hope the rays have the same effect in human brains.

In a study published in May in the journal Cell, scientists exposed a group of mice to UVB rays, a short-wave ultraviolet light, for two hours--the equivalent of 30 minutes of sunlight. Researchers then evaluated the mice’s motor skills with a rotarod test, in which the mice balance on a rotating rod, followed by a memory trial in which mice had to sniff out the novel object in a familiar setting.

Exposure to mock-sunlight increased levels of urocanic acid in the mice’s blood, which was converted in the brain to glutamate, a neurotransmitter released at the motor cortex, where voluntary movement originates, and hippocampus, the brain’s main storage unit for long-term memory.

The UVB-exposed mice showed significant improvement in the motor skills and object recognition tests compared to the control mice, researchers said.

GettyImages-3459981 A mouse seen at a lab at the Tokyo University of Agriculture on April 23, 2004, in Tokyo. Mice improved their memory and learning ability after exposure to UV rays, results scientists hope to replicate in human trials. (Photo by Koichi Kamoshida/Getty Images)

If sunlight could generate memory and learning improvements in mice, the same could be true for the human brain, researchers hope. Lead researcher Xiong Wei told China Daily he plans to use the research to understand the molecular functioning of Alzheimer’s and Parkinson’s diseases and identify them before they destroy the brain.

“To diagnose the diseases in their early stages, which has been very hard, we wanted to find some small molecules that could serve as biomarkers,” he said.

Though only 10 percent of UVB light makes it through the earth’s atmosphere, a little can go a long way. Exposure can stir up vitamin D production in the skin, generate nitric oxide that improves cardiovascular health and increase endorphin release for a mood boost.

The risks of too much UV exposure are numerous, most notably increased likelihood of blindness and skin cancer, including melanoma, the deadliest variety. The World Health Organization recommends five to 15 minutes of sun exposure two to three days a week during the summer and limiting outdoor activity from 10 a.m. to 4 p.m. when the sun’s UV rays are strongest.

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