The patches of harmful proteins that interfere with brain function have been partially erased in mice using nothing but light and sound.
Research conducted by MIT has found strobe lights and a low buzz can be used to recreate brain waves lost in the disease, which in turn removes plaque and improves cognitive function in mice designed to show Alzheimer's-like behavior.
It's a bit like using light and sound to activate your own brain waves to fight the disease.
This technique has not yet been clinically tested in humans, so it's too early to get excited – brain waves are known to work differently in humans and mice.
But, if replicated, these early results suggest a possible economic and drug-free method to treat the common form of dementia.
How does it work?
Advancing a previous study that showed a flashing light 40 times per second in the eyes of engineered mice treated their version of Alzheimer's disease, the researchers added the sound of a similar frequency and found a marked improvement in the results.
"When we combine visual and auditory stimulation for a week, we see the commitment of the prefrontal cortex and a very dramatic reduction of amyloid", says Li-Huei Tsai, one of the researchers of the Picower Institute for Learning and Memory of MIT.
It is not the first study to investigate he ate the role that sound can play in clarifying the brain of tangles and groups of tau and amyloid proteins at least partially responsible for the disease.
Previous studies showed ultrasound explosions that caused the blood vessels to lose enough to allow powerful treatments to slip into the brain, while encouraging experts in the removal of nervous system waste, microglia, to take the rhythm.
Several years ago, Tsai discovered that the flickering of light at a rate of about 40 flashes per second had similar advantages in mice designed to build amyloid in the nerve cells of their brain.
"The result was so stunning and so robust, it took some time for the idea to sink, but we knew we had to find a way to try the same thing in humans," Tsai told Helen Thomson to Nature at that time.
The only problem was this effect was limited to the visual parts of the brain, lacking key areas that contribute to memory formation and recovery.
While the practical applications of the method seemed somewhat limited, the results indicated a way in which oscillations could help the brain recover from Alzheimer's disease.
As neurons in our brain transmit signals, they also generate electromagnetic waves that help keep remote regions synchronized ̵
Such a set of oscillations is defined as gamma-frequencies, which propagate through the brain at about 30-90 waves per second. These brain waves are more active when we pay close attention, looking for our memories to make sense of what is happening.
Tsai's previous study had suggested that these gamma waves are hindered in individuals with Alzheimer's and may play a key role in the pathology itself.
Light was just a way to trick parts of the brain into a buzz in the key of the range. Sounds can also handle it in other areas.
Instead of the high-pitched cry of ultrasounds, Tsui used a much lower buzzing noise of only 40 Hertz, a sound just high enough for humans to hear.
Exhibiting their mouse subject to only one hour of this monotonous humming every day for a week led to a significant decrease in the amount of amyloid accumulation in the auditory regions, while also stimulating those microglial cells and blood vessels.
"What we have shown here is that we can use a completely different sensory modality to induce gamma oscillations in the brain," says Tsai.
As a further advantage, it has also helped to free the nearby hippocampus – an important section associated with memory.
The effects were not only evident in the brain chemistry of test subjects. Functionally, the mice exposed to the treatment achieved better results in a series of cognitive tasks.
The addition of light therapy from the previous study saw an even more dramatic effect, erasing plaques in different areas of the brain, including the prefrontal cortex. Even those rubbish microglia went to the city.
"These microglia accumulate on each other," says Tsai.
Discovery of new mechanisms in the way nervous systems eliminate waste and synchronize activity is a huge step forward in the development of treatments for all types of neurological disorders.
The translation of discoveries like this into the human brain will require more work, especially when there are potential contrasts in the way in which gamma waves appear in mice and in the human Alzheimer's brain.
So far the first safety tests have shown that the process seems to have no clear side effects.
This research was published on Cell .