Nat Neurosci: Xue Tian team discovers neural loop linking circadian rhythms to depression

In addition to producing vision, light regulates a variety of physiological functions, including emotionsAlthough light therapy used during the day is known to have antidepressant properties, there have also been reports of excessive light exposure at night associated with depressive symptomsUntil now, the neural mechanisms of the circadian differences affected by this light are unknownby using the paradigm of night light (LAN) in mice, the Team of the University of Science and Technology found that LAN induces depressive-like behavior without interfering with circadian rhythmsThe effect is mediated by a neural pathway that ranges from the neurosection cells expressed in retinal melanin to the peripheral leaf nucleus (dpHb) on the back side to the transverse fiad (NAc)importantthing is that dpHb is controlled by circadian rhythms, which are more excited at night than during the dayThis shows that the IPRGC-dpHb-NAc pathway gives priority to the transmission of light signals at night, thus mediating the depression-like behavior induced by LANthese findings may be related to the effects of night lighting on mental health, which is prevalent in the industrial world