Science and technology reporter Liu Xia.
The latest research by American scientists has found that sound and light stimulation at 40 Hz can enhance the ability of mouse brains to remove waste products, especially toxic proteins such as amyloid. These proteins can cause memory and concentration problems. Related**Published in the Feb. 28 issue of the journal Nature.
Cross-section of the mouse brain, showing that neurons appear to release molecules that better remove toxins. Nature
Previous studies have shown hope in Alzheimer's disease mice, with the help of sound and flashing lights, but the mechanism of action has been a mystery. In 2016, a team led by Professor Lihui Cai, a neuroscientist at the Massachusetts Institute of Technology, began studying whether 40 Hz sound and light stimulation can improve the cognitive abilities of people with Alzheimer's disease. They subjected mice to 40 hertz flashing light and sound stimulation for one hour a day, and the results showed that the method reduced the accumulation of amyloid in the brains of Alzheimer's disease mice.
In the latest study, Cai Lihui et al. carried out a series of experiments on transgenic mice to try to reveal the mystery of the **. These transgenic mice typically produce amyloid as they age and have a worse memory than the average mouse. The study found that these particular lights and sounds appear to enhance the function of the drainage system of the mouse brain, the lymphoid system.
Studies have shown that when animals are exposed to light and sound, their brain amyloid levels decrease. However, Cai Lihui et al. also found that in the ** process, more cerebrospinal fluid entered the brain of mice, and more waste fluid was discharged from the brain through lymphatic vessels. The reason appears to be that nearby blood vessels have greater pulsations, which help propel lymphoid fluid through the blood vessels; It may also be because there is more fluid flowing into the lymphoid system.
The team also found that interneurons, a specific type of brain cell, appear to increase lymphatic flow by releasing molecules called vasoactive intestinal peptides. When the team chemically blocked the production of this molecule, sound and light** failed to increase the clearance of amyloid.
McCann Nedgold of the University of Rochester commented in Nature Medicine that a deep understanding of the mechanisms of toxin clearance in the brains of mice could help unleash their potential.