Studies are producing mounting evidence that light flickering and sound clicking at the gamma brain rhythm frequency of 40 Hz can reduce Alzheimer's disease (AD) progression and treat symptoms in human volunteers as well as lab mice. In a mouse model, researchers reveal a key mechanism that may contribute to these beneficial effects: clearance of amyloid proteins, a hallmark of AD pathology, via the brain's glymphatic system, a recently discovered "plumbing" network. The paper describes a series of experiments showing that when sensory gamma stimulation increases 40 Hz power and synchrony in the brains of mice, that prompts a particular...