Light at night affects the psycho-emotional state

A study published in the Proceedings of the National Academy of Sciences showed that if the brain is regularly exposed to artificial light at night, it can lead to symptoms similar to depression. The experiments were conducted on arboreal tupayas, which are day—active animals that are genetically close to humans.

For three weeks, the animals were exposed to bright blue light daily for two hours after dark. The results were not long in coming: tupai’s interest in sweets decreased (which is one of the signs of apathy in animals), they began to move less and memorized new information worse.

But the most interesting thing is not in behavior, but in the brain. Scientists have discovered a specific chain of neurons that starts working when exposed to light. First, the signal comes from the eyes directly to a small area of the brain — the perihabenular nucleus. From there, to the area that governs emotions and motivation. It is her work that is disrupted by depression.

When the researchers turned off the activity of these neurons, the light no longer caused alarming effects. Moreover, the study of genes has shown that night light can change the activity of those DNA regions that are associated with depressive states.

“This is a serious reason to think,” says Professor Yao Yonggang, one of the authors of the study. — We have understood the ways in which light interferes with the emotional sphere. Now we know where to look for a solution.”

Light is certainly a boon to civilization. It allows us to work, study, read and communicate, even when it’s night outside. But experts insist: it is worth being careful about the lighting mode. Especially in the evening and before going to bed. Perhaps by turning off the lights, we turn on our peace of mind.