Sometimes, even your hoped for results astound you. Like, Dr. Hannah Iaccarino (MIT) found when she zapped a mouse with induced (but initial stages of) Alzheimer’s disease. The light caused brain wave induction (roughly 40 oscillations per second [Hz]). And, then she found that the toxic protein levels of amyloids halved.
So, she repeated the experiment. Obtaining the same results. So a slew of other researchers tried the concept. Getting the same results. (Hannah and Anthony Martorell, and Dr. L-H Tsai have published their results. Along with Dr. AC Singer, A Rudenko, F Gao, TZ Gillingham, H Mathys, J Seo, J. Krisskiy, F Abdurrob, C Adaikkan, RG Canter, R Rueda, EN Brown, and ES Boyden- alll from various MIT departments; the team is multidisciplinary on purpose. The article: Gamma frequency entrainment attenuates amyloid load and modified microglia, published in Nature. )
Previous studies outlined the molecules that accumulate (or form) in patients. Scientists have also narrowed down which genes are involved in the onset of Alzheimer’s. But, studying the brain as a whole, as a system- that’s not been a big avenue for research.
One factoid: In later stage patients, amyloid plaques that accumulate in the brain are associated with a decrease in the brains’ gamma wave strength. (Gamma waves traverse the brain at 40 Hz, when the brain is involved in attention-setting activities like forming memories or solving problems.)
Dr. Tsai, the senior researcher on this project, wanted to discern if gamma waves attenuate in the brains of those afflicted with early state Alzheimer’s. His group had induced gamma waves with optogenetics in a previous research study, so they knew how to try that with new subjects. (Neurons within the hippocampus are engineered to respond to lasers; the hippocampus is the site of memory formation.) The team chose a mouse with five human genes that are associated with Alzheimer’s; the problem is while these mice had elevated levels of amyloids, they lacked plaque formations.
Dr. A. Singer discerned that these mice had weak gamma signals; non-model [conventional] mice had normal gamma signals.
And, while the research demonstrated that inducing the brain waves reduced amyloids by 50%, the scientists had no idea why that occurred. So, they cast a wide net. (This is called discovery science, where one collects vast amounts of data and searches for patterns with which an hypothesis can be formed).
The wide net worked. The gamma waves altered the behavior of microglia, immune cells that “cleanse” the brain of proteins (including amyloids). Moreover, with increased gamma wave strength, these cells increase in number, size, and activity.
Dr. E. Brown, a physician on the team, had strong reservations (as would we all) about using optogenetics in patients. After all, we don’t want optical fibers implanted in human brains. It was his suggestion to flicker light into the subject’s eyes. (Other researchers had found that the visual cortex mimics the activity patterns of light shining through patients’ eyes. No one had ever tried oscillations, though.)
Now, the team needed to create a controllable, flickering LED. Dr. Boyden of the MIT Media Lab and the McGovern Institute of Brain Research solved that problem.
This enabled the team to determine that not only were amyloid levels halved in early state Alzheimer’s patients- their technique also removed plaques from later stage Alzheimer’s subjects. (It seems that Alzheimer’s symptoms in patients normally are discerned AFTER the formation of plaque, long after the amyloid levels change.)
The next stagesfor the research include discerning how long the results last. Will subjects have to encounter multiple sessions with the lights?
And, given how the brain responds to sensory stimulation, will sound or, perhaps, touch create similar responses? Because the results need to be induced in other portions of the brain (besides the hippocampus), to ensure the eradication of the disease.
This could be a big step in treating Alzheimer’s.