Even if the new research does not yield a treatment for Alzheimer's, it is expected to deepen understanding of a key player in the disease - the brain's dedicated immune system - and point to ways it can be used to fight the disease.
But the new research has already prompted creation of a start-up company - Cognito Therapeutics Inc.
- to approach the Food and Drug Administration about clinical trials, and to explore ways to deliver precisely calibrated flickers of light to human research subjects.
But the authors of the new research held out hope that the light therapy might induce gamma oscillations, or their immune-boosting effect, more broadly in human brains, or that some change in delivery of the light might extend its effects to brain regions, such as the hippocampus, that are profoundly affected by Alzheimer's.
It's not hard to induce gamma oscillations naturally: Our neurons achieve such synchrony when we are learning, paying attention or engaging our short-term memory.
In mice, these effects were limited to the visual cortex.
In humans with Alzheimer's, that's not one of the brain regions that gets gummed up early or significantly by amyloid plaques.
The effect was dramatic in mice bred to develop the sticky brain plaques and tangles that are a hallmark of Alzheimer's disease in humans.
After only an hour in front of the lights, the scientists found reduced levels of amyloid protein in the visual cortices of the animals.
Compared to mice who did not get the weeklong light therapy, those that did had 67 percent fewer amyloid plaques - the clumps of amyloid protein that appear to gum up the function of a brain in the grips of Alzheimer's.