How does light therapy affect the brain?

arts/

It is well known that humans are quite sensitive to light, and in fact, the so-called "biological clock" or circadian rhythm has always existed in every cell and organ of the human body. The suprachiasmatic nucleus (SCN), located in the anterior part of the hypothalamus and above the optic chiasm, is also an important biological center that regulates the rhythms of various life activities, from eating and sleeping to hormone secretion.

For example, for sleep, when light shines on the retina, neurons transmit "daytime" signals to the suprachiasmatic nucleus, and the suprachiasmatic nucleus can uniformly regulate many biological clocks in the body, synchronize them, and communicate with the outside world. The clues that the environment changes day and night are consistent.

Of course, the impact of light on the human body is far more profound than this . In 1984, after Rosenthal et al. found that light can improve depression to a certain extent, light therapy has become an important therapy for seasonal depression, and it is even considered to have the same effect as selective serotonin reuptake inhibitors. At present, the scope of application of light therapy has gradually expanded from the initial seasonal depression to a variety of neuropsychiatric diseases such as bipolar disorder, depressive disorder, schizophrenia, and Alzheimer's disease, but the mechanism of action is still unclear.

In fact, as a safe and green physical therapy, light therapy has been tried and made progress in the treatment of various mental disorders, but the mechanism is still unclear .

In Shanghai, for example, a specific part of the brain is responsible for how our behavior changes with the number of seasonal days, according to the researchers. The suprachiasmatic nucleus (SCN), hidden in the hypothalamus of the human brain, is responsible for keeping track of time in the body. Therefore, changes in sunlight can significantly affect these neurons. We can use this to help with light therapy, scientists say.

The SCN is made up of approximately 20,000 neurons and is responsible for following the body's 24-hour cycle, regulating all physical, psychological and behavioral changes in the body . The cells and neurons within the SCN evolve and change as the length of sunlight the body is exposed to on a daily basis changes. They think this change may also be effective in light therapy. Light therapy relies heavily on creating an artificial sensation for the human body. And with this new study, scientists have managed to do just that. Not only that, but they believed they might understand the connection of sunlight to the human body and its behavior.

Of course, as far as light therapy itself is concerned, the influencing factors may come from many aspects, such as light intensity, light time, light treatment course, light of different wavelengths, etc. But in essence, this is still a technology worthy of our belief.