Treatment of Alzheimer's disease finds new hope in lights and sounds. Scientists discover that using specific visual and auditory stimulations may clear brain plaques in mice, and possibly in humans too.

The research demonstrates that inducing a mix of distinctive brain waves, technically referred to as gamma oscillations, improves the appearance of the plaque-plagued parts of the brain responsible for memory and cognition.

The study is published in the journal Cell.

Turn The Lights On, It Helps

The team relates back to their 2016 investigation, wherein flickering lights improved the brain waves restoration of mice that are genetically predisposed to have clinical manifestations of Alzheimer's. They specifically induce the mice with 40 hertz light for an hour. Results show that this intervention decreases the white deposits in the brain, as well as other pathogenic signs linked to Alzheimer's. Furthermore, it triggers activity of immune cells called microglia, which is known to clean up debris.

The findings of the said past study are only observed in the visual cortex of the brain. For the latest study, they wanted to know if they are able to extend the therapy effects to other regions using auditory stimuli.

Sound Effects Improve Findings

The scientists introduce sound stimuli and observe its effects on the cognition of the subjects. Findings reveal that after a week of therapy, their cognitive abilities improved as evidenced by better performance in going through a maze, which requires memorization of key indicators. The mice were also able to identify objects that have been exposed to them in the past.

Ultimately, the group observes that the changes take place, not only in the microglia but also in the blood vessels — signaling that it may pave the way for riddance of plaques.

Two Is Better Than One

If separate stimulus produces good results, why not combine them? The scientists proceeded to do just that and to their shock, it yields better outcomes. The clearing of the plaques reaches wider, including the region of the brain that manages higher cognitive functions. The microglia respond better as well.

"These microglia just pile on top of one another around the plaques," says senior author and MIT's Picower Institute for Learning and Memory director Li-Huei Tsai. "It's very dramatic."

One key observation is that putting the subjects under treatment for a week, and then stopping and waiting for another week to perform the testings reduces the promising effects. This suggests that therapy should be administered continuously.

Future Is Bright With Lights And Sounds

Tsai says their team is able to show that widely varied sensory stimuli may be used to bring gamma oscillations in the brain.

The group's work is not yet finished. Their next step is to find out the effects of gamma oscillations to certain brain cells, in the pursuit of unveiling the processes leading to their discovery in the molecular level. They also like to know why 40 hertz is the specific frequency that yields good results.

Neuroscientists begin testing the combined treatment to qualified healthy volunteers and they are now looking to involve individuals with symptoms of early-stage Alzheimer's.

Although mice and humans are two very different species, Boston University Mathematics and Statistics professor Nancy Kopell thinks the study is a cause for positivism. For her, the research and other related investigations have the qualities for big clinical impacts in Alzheimer's and other inflammatory brain conditions.

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