Brushyour phone before bed is prone to depression? Nature sub-issue reveals the nerve mechanism of night-time blue light 'depressing'

What do you usually do before you go to bed? If you're always watching TV for a long time or staring at your computer or cell phone, the following research paper, just published online in Nature Neuroscience, may give you some health warningsA team of researchers led by Professor Xue Tian of the China University of Science and Technology and DrZhao Huan of Hefei University found that increasing the amount of blue light at night affects specific neural loops in the brain, causing depression-related symptomsIn their paper, the scientists note that light affects the physiological functions of mammals, including moodOn the one hand, many studies have shown that the right amount of solar energy during the day to raise mood, the use of "light therapy" to supplement the light, can alleviate the symptoms of depressed patients; Although the mice's circadian preferences were the opposite of those in humans, their behavior was also affected by daily light changes and circadian rhythmsThe team first designed experiments to verify thisThey irradiated the mice with blue light for two hours each night for three weeksWith increased night time illumination, the mice's circadian rhythms were not altered, but some strange behavior gradually occurredFor example, when forced to swim, it is a love of the state of immobility to give up; Because these behaviors are similar to human depression, scientists define them as depression-like behaviorsNot only that, but the mice did not recover immediately after the nightly blue light exposure, and the depressive behavior continued for up to three weeksSo why does increased nightlight cause depressive behavior? Next, the team used neurotracer tools to find a special neural loop that revealed the possible neural mechanisms behind the phenomenonSpecifically, this neural loop begins in the retina, where a class of neurocytoclia cells , or ipRGC , are distributed, and they express a protein associated with regulating the biological clockThese cells are sensitive to light, and when activated by light, they send signals to the back side of a nuclear group called the outer nucleus of the brain (dorsal perihabenular nucleus, or dpHb), where a portion of nerve cells are then projected onto the volt nucleus (NAc)These two brain regions are closely related to depressive symptomsAmong them, the outer nucleus is often referred to as the brain's "anti-reward center", medialing a lot of negative emotions, its overactivity will induce depression-like behavior; When the researchers blocked the neural connection between the outer reins and the volt nucleus in the mouse brain, they prevented nighttime light from inducing depressive-like behavior, suggesting that the neural loop played an important roleOne might ask, since this neural loop is activated by light, what to do during the day? The study authors compared it and found that nighttime light activates the neural loop much more than during the day, which may explain why daylight does not cause behavior changesIn the discussion of the paper, the scientists also pointed out that the findings can be inferred from humans, after all, mouse experiments have limitations, such as the mice themselves hate light, so the negative mood toward light may be more intense Moreover, behaviors such as not favoring sugar water can also be caused by other causes, not necessarily the same as real depression in humans However, the authors conclude that to understand how increased nighttime light affects mood, finding out the neural pathways that affect the brain by nightlight is the first step If light activates the same neural loop in the body, these results may help explain how excessive nighttime light affects humans and why depression symptoms are associated In fact, it wasn't long before scientists found the ipRGC nerve cell in the human retina, the first stop of this neural loop With the progress of industry and technology, night lighting is becoming more and more common, many people live under the neon lights of the "Night City", to the landscape lights off late at night, home and continue to accompany the blue light emitted by electronic devices However, humans have adapted to the light of day and night over millions of years of evolution, and our health and mood may be quietly negatively affected when the night light is excessive (Original title: Is it easy to be depressed by brushing your phone before bed? Xue Tian/Zhao Huan team reveals the neural mechanism of night-time blue light "depressing"