Progress in the study of nighttime light-induced negative emotions

Recently, Xue Tian, School of Life Sciences of the Chinese University of Science and Technology and key laboratory of brain function and brain disease of the Chinese Academy of Sciences, described for the first time the neural loop structure and function of the precipice-induced depression-like phenotype; The results were published online June 1 in Nature Neuroscience, using the results of a circadian rhythm-gated subcortical group for nighttime-light-light-de-discar-cars in micelight is the foundation of life, the Earth's life evolved under the light conditions of alternating day and night, evolving a series of light perception and light regulation neurophysiological functions, in addition to imaging vision," including the biological clock's light regulation, sleep, fear of light, pupil light reflection, melatonin expression and other physiological functions collectively known as "non-image vision" (non-image-forming vision)In the history of human evolution for thousands of years, the existence of meaningful night-time rich light is only a hundred years after the Industrial Revolution, and evolution is far from allowing humans to adapt to this artificial light environment changesA range of public health evidence suggests that prolonged exposure to abnormal nighttime light can lead to depression-like mood and cognitive impairment, but little is known about the neural mechanisms behind itrecent neuroloop study of light-regulating mood saucy, a study (Fernandez etal.Cell, 2018) shows long-term fragmented light and dark stimulation that can trigger negative emotions through projection from the retina to the outer rim of the reins (perihabenular nucleus, pHb)However, whether the disturbance of light or rhythm affects the mood is still unknown, the complete light control emotional neural loop is not depictedWhat's more, the light of the day tends to regulate human emotions head-on (Huang etal., Neuron, 2019), the principle behind the effects of this diametrically opposed day and night light on emotions has been a mysteryto answer these questions, Xue Tian's team built a night light interference model (light at night, LAN) to simulate the current social abnormal lighting patternsBlue light exposure, which lasts for three weeks and lasts from 9-11 to 2 hours per night, can cause the mice to exhibit depressive behavior without disturbing rhythms or sleepNon-imaging visual function is thought to be mediated by a class of photosensitive cells in the retina that are different from the cone stoops - the self-sensitive photorerel nerve cell (ally photosensitive retinal ganglion, ipRGCs)Using theofgenetically modified animals that are missing from the visual rod cells, cone cells, and ipRGC, the team found that ipRGC plays a full and necessary role in the process of inducing depression in LANto further reveal the central structure of the mediated LAN, the team found that ipRGCs were projected onto pHb, and that the mood-related behavior of mice was no longer affected by LAN after the damage to pHbAt the same time, the use of light genetic activates the projection of ipRGC to pHb, which can also induce depressed-like performance in mice These results fully verify that pHb is an important loop node for the role of mediated LAN Further loop studies have found that the back side of the pHb (dorsal pHb, dpHb) is projected onto the nucleus accumben, NAc, and the abdominal side (ventral pHb, vpHb) is projected onto the prefrontal cortex (medial prefrontal cortex, mPFC) NAc is a nuclear group closely related to reward, while mPFC is closely related to emotion and advanced cognition The team inhibited the input of pHb to mPFC and NAc, respectively, through a Av virus tool, and the results confirmed that only inhibition of dpHb-NAc projection would affect the role of LAN The evidence that dpHb-NAc projection, which is directly activated at specific times of the night for three weeks, does not depend on nightlight to induce depressive-like performance, and these evidences reveal the central role of dpHb-NAc projection in LAN-induced negative emotions finally, to delve into the mechanisms by which light regulates emotions at different times (day/night) Using single-cell diaphragm clamps and in-body fiber recordings, the researchers found that dpHb neurons projected on nAc were more excited at night than during the day and were more likely to release action potentials, while vpHb neurons projected onmPFC were not similar It is shown that the dpHb neurons projected onn to NAc act as valves controlled by circadian rhythms and are open only at night, allowing night-time light signals to regulate nAc, a nuclear group closely related to reward, through dpHb, which in turn induces negative emotions Further research by the researchers speculated that the neuroloop of ipRGCs-dpHb-Nac may have prevented predators from being exposed to light during day and night rotation under normal physiological conditions If the loop is also present in humans, it can be hijacked by artificial light environments at night, which induces negative emotions the study for the first time elaborated on the loop foundation and rhythmic gating mechanism of night light-induced negative emotions, these findings can prompt the mechanism of negative emotions such as night light interference (urban lighting or the use of electronic devices such as mobile phones) leading to depression to a certain extent, and it is of great significance for people to correctly understand the potential harm of night-time excessive lighting and explore prevention and control methods (
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