Scientists are bringing a bright new idea to the often-discouraging search for ways to treat Alzheimer’s disease.
In experiments on mice, scientists used light and sound to orchestrate a series of episodes that were marked by electronic synchrony inside the animals’ brains. Prompted by a flickering light and a pulsating buzz — both timed to fire 40 times per second — their brains began to hum to the same frequency.
The results, published in the journal Cell, are yielding some powerful insights about what may go wrong in Alzheimer’s disease, and how that process might be halted or reversed.
Whether the strategy, called gamma oscillation entrainment, is as effective in people will soon be tested. MIT neuroscientist Li-Huei Tsai acknowledged that the success of the new strategy in humans is a big if. But she said it has an advantage that drugs, implants and surgical procedures do not: Without breaching the skin, it appears to recruit special cells to do their healing work inside the brain.
The research builds on Tsai’s work using a technique called optogenetics and then visual stimulation to prompt gamma wave synchrony and correct faulty signaling in the brain. It worked, but only in the visual cortex, which isn’t typically under attack in Alzheimer’s.
In the new study, researchers added acoustic stimulation. And when mice bred to develop Alzheimer’s-like symptoms were exposed to both, researchers saw that the neurons in several of their brains’ key memory circuits began humming along at the same frequency.
After the sessions, an army of newly energized immune cells descended on several areas of the brain. Normally idle as Alzheimer’s disease takes hold, these debris-clearing cells, called microglia, began vacuuming up the sticky plaques and tangles of protein that gum up the brains of those with the memory-robbing disorder.
The study’s central finding — that inducing electrical synchrony touched off such a widespread range of effects — suggests there might be a single key lever that can preserve or restore order in brains made “noisy” by age and disease.