Alzheimer’s disease is a neurodegenerative disorder characterized by progressive memory loss, spatial disorientation, cognitive dysfunction, and behavioral changes. It is the most common form of dementia, affecting nearly 50 million people worldwide. The primary pathological hallmarks of Alzheimer’s disease include amyloid-beta plaques and tau tangles. Abnormal electrical activity in the brain can worsen the condition. A recent review describes findings from two rodent studies suggesting that stimulating gamma waves in the brain may reverse the pathology and symptoms of Alzheimer’s disease.
During wakefulness and periods of REM sleep, the human brain exhibits spontaneous rhythmical activity in the form of fast-moving gamma waves. These waves are evoked by intense attention, conditioned responses, tasks requiring fine movements, or sensory stimuli.
The studies utilized mice that were predisposed to Alzheimer’s disease. These mice often exhibit diminished gamma wave activity. The authors of the studies exposed the mice to visual and auditory stimuli that were designed to promote gamma wave activity.
Following exposure to visual stimuli alone, the mice exhibited reduced amyloid burden and structural changes in the microglial cells in the visual cortex of their brains. These structural changes were consistent with increased phagocytic capacity, which is crucial for the clearance of apoptotic or necrotic cells and the removal of amyloid-beta. Exposure to auditory stimuli alone had similar effects on microglial activity and amyloid burden in the auditory cortex of the mice’s brains, but the mice also exhibited improved performance on several hippocampal-dependent tasks and improved brain vasculature.
When the mice were exposed to combined auditory and visual stimuli to promote gamma wave activity, the amyloid burden was reduced throughout the neocortex, the area of the brain that processes sensory, motor, language, emotional, and associative information. In addition, the microglia in several regions of the brain exhibited a clustering pattern around the amyloid plaques that facilitated clearance.
These findings suggest that non-invasive techniques that promote gamma wave activity in the brain may be useful in treating people with Alzheimer’s disease.
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