With the medical sciences, often the best insights come from studying the body’s ways of healing itself. We’re all familiar with the basics—white blood cells that attack invaders—and we’re discovering new details all the time. Apparently, for example, inflammation acts like a beacon to bring the immune system’s defenses to the right place. The best medicine comes from within the body.

Dr. Li-Huei Tsai, director of the Picower Institute for Learning and Memory at MIT, might have had this general principle in mind when she set up her experiments with mice who had been caused to develop Alzheimer’s disease. She exposed them to lights that flashed at the same frequency as the natural oscillation of neurons. She was encouraging the brain to resume its natural rhythms that had been disrupted by Alzheimer’s disease.

To all our benefit, she proved her theory, discovering that the lights appeared to increase the efficacy and strength of the brain’s natural defense against both the tau tangles and the amyloid beta plaques. The lights seemed to activate cells called microglia, which clean up the toxic build-up. The results she observed in the mice were dramatic, both in the improvement of their cognitive abilities and the actual reduction of tangles in their brains.

It doesn’t feel like a coincidence to me that light is at the heart of her discovery. How fitting that it is light, an age-old symbol of undying hope in the human mind, that shows promise of encouraging the human brain to heal itself.