“The brain is really complicated. A cubic millimetre of your brain will have a hundred thousand cells called neurons, connected by a billion connections called synapses. It’s the most complicated computer we can think of.”
Edward Boyden, professor of neurotechnology at the MIT McGovern Institute, won the 2018 Canada Gairdner International Award for his discovery of optogenetics: a technique that illuminates how the brain works, in hopes of uncovering better strategies to treat brain diseases and disorders.
Using optogenetics and other physics- and chemistry-based strategies, Boyden is trying to map the brain and all its wires and connections. His techniques can also be applied to control the brain and find ways to repair it.
“It turns out that genes, pieces of DNA, in the natural environment actually encode little solar panels: molecules that convert light into electricity,” says Boyden. “And it’s important to know that brain cells compute using electricity.”
That means that using optogenetics, researchers can introduce these solar panel genes to brain cells, and that they can then activate them directly by shining light on selected parts of the brain.
Boyden first takes these special genes from many sources, including bacteria, fungi, and algae. Borrowing from gene therapy methods, he then adds these genes to brain cells so that he can manipulate them.
“That’s how we can activate memories, shut down seizures, all sorts of other mysteries of the brain that we can solve by perturbing in a causal way what’s happening within the brain,” adds Boyden.
These experiments can show how activating certain areas or patterns of activity in the brain influence its function. While optogenetics is designed for research use, Boyden is also manipulating the brain using light and sound in other innovative ways.
“My colleague Li-Huei Tsai has used our technology to discover a pattern of brain waves that activates the brain’s immune system,” says Boyden.
“This brain wave will actually turn on cells called microglia, and these go out and clean up the junk that builds up in Alzheimer’s disease.”
Activating this repair mechanism could have major implications for treating disease without using drugs.
“Inspired by that, we have been designing movies that people can watch that would activate the same pattern of brain activity, and maybe help treat Alzheimer’s disease,” adds Boyden. “We’ve begun the human trials already.”
Treating Alzheimer’s with light and sound to manipulate the brain could represent a big shift in the treatment paradigms currently under investigation.
These therapeutic movies have shown remarkable improvement in mouse models, and have been shown to be safe when shown to healthy human volunteers. The next step is to test the same technology with early-stage Alzheimer’s patients.
“Over a billion people around the world have some kind of brain condition, and basically nothing can be cured,” says Boyden.
“So if we could help people with Alzheimer’s and schizophrenia, depression and addiction, epilepsy and Parkinson’s along the way, that would make me very happy.”