Researchers at MIT noticed that mice developing Alzheimer's-like pathology showed weakened gamma brain waves, the fast electrical rhythm tied to attention, even before plaques appeared. They wanted to know whether restoring that rhythm artificially would change anything downstream.
The team used light pulses to drive specific neurons at exactly 40 pulses per second in mice, matching the natural gamma rhythm, and measured amyloid-beta levels afterward. The treated brain tissue showed reduced amyloid, and the brain's immune cells changed shape and gathered around the protein.
The researchers then built a simpler, non-invasive version: a light flickering at 40 hertz in front of the mice's cages for an hour a day. It reduced amyloid in the visual cortex of young mice and cut plaque buildup in older, already-affected mice. Early human trials of light and sound have followed with preliminary results, and a 2023 study from another lab could not reproduce the amyloid drop in mice.
Read the original study
Iaccarino et al., Nature, 2016 · doi.org/10.1038/nature20587
A flicker, tuned to the brain's own rhythm.
Source
- Iaccarino, H. F., Singer, A. C., Martorell, A. J., Rudenko, A., Gao, F., Gillingham, T. Z., Mathys, H., Seo, J., Kritskiy, O., Abdurrob, F., Adaikkan, C., Canter, R. G., Rueda, R., Brown, E. N., Boyden, E. S., & Tsai, L.-H. (2016). Gamma frequency entrainment attenuates amyloid load and modifies microglia. Nature, 540(7632), 230–235. https://doi.org/10.1038/nature20587