A recent study has shed light on how constant exposure to artificial blue light at night can impact our mood. Researchers at the University of Science and Technology of China, the Kunming Institute of Zoology, and Hefei University conducted experiments on tree shrews—diurnal mammals genetically close to primates—and found that just two hours of blue light each night for three weeks led to depression-like behaviors. 😮
The animals showed a 20% drop in sucrose preference, reduced exploratory behavior, and memory deficits. By using advanced neural tracing techniques, the team uncovered a unique visual circuit: specialized retinal ganglion cells send direct signals to the perihabenular nucleus (pHb), which then projects to the nucleus accumbens, a key center for mood regulation.
Interestingly, when the pHb neurons were chemically silenced, the depression-like symptoms did not appear, suggesting that the circuit plays a crucial role in how nighttime light affects mood. RNA sequencing further revealed that these light-induced changes corresponded to shifts in depression-related genes. In the words of Professor Yao Yonggang from the Kunming Institute of Zoology, "These findings give us both a warning and a roadmap."
As light pollution and screen exposure rise in our modern, vibrant lives, this study prompts us to think about the unseen costs of nighttime brightness. It paves the way for targeted interventions that could help balance productivity and well-being in our tech-driven world. 🌃
Reference(s):
Study finds link between nighttime artificial light and depression
cgtn.com
