Stanford researchers see the head light

Oct. 8, 2010, 3:01 a.m.

A revolutionary treatment for mental illness beyond manipulating brain chemicals may be on the horizon of bioengineering.

Stanford researchers are working to explore a means of controlling neural activity using light through gene manipulation to trigger muscle movement.

Optogenetics—the technique of using light in gene control—is an emerging tool that holds powerful potential for bioengineers, particularly in the field of neuroscience. Building on the 2002 discovery of channelrhodopsins, light-sensitive proteins found in green algae, the research team engineered a bold invention: a virus that assists in delivering the algae gene into brain cells.

These brain cells are stimulated by light of varying wavelengths.

“Neurons can be inhibited with red light, while a shift to blue light can excite them,” said neuroscience Ph.D. candidate Viviana Gradinaru, who is working alongside 41 other scholars on the research.

By exposing the cells to light of different wavelengths, scientists can now control which cells to “turn off” and which cells to “turn on.” One of the weaknesses that this research addresses is the lack of precision in neural activity mapping.

Gradinaru said the Stanford team developing optogenetic brain stimulators to control brain function and its applications to psychiatric disorders.

Advances in neuroscience research have long been limited to the technology used in neural imaging scans. Scientists could measure electrical signals from individual neurons or observe the brain as a whole using magnetic resonance imaging.

But before optogenetics, no technology allowed researchers to look at specific clusters or areas of neurons, limiting current knowledge on how neurons affected mental and neurological illnesses such as schizophrenia and clinical depression.

This opens up exciting and new opportunities for scientists seeking to treat diseases that target specific types or clusters of not only brain cells but potentially cells in other parts of the body as well.

“It can also be applied to all excitable cells, such as muscle cells, gut cells, heart cells,” Gradinaru said. “With the opto-xr tools engineered to control intracellular signaling pathways, there lies the possibility of expanding that technique to all types of body cells.”

Although the field of optogenetics is young, it has received enormous enthusiasm from researchers all over the world. At least 600 research university labs have expressed interest in the technology.

Karl Deisseroth, the associate professor in bioengineering and psychiatry leading the research, seems to have no trouble keeping up with new research avenues. He’s already published five papers since 2007.

“A lot of people thought about [the idea of using protein to control human cells],” he told Forbes Magazine in July. “But nobody was crazy enough to try it. We were.”

He was unavailable for an interview with The Daily.

There is still much work to be done—the data collected are solely based on animal models.

“The ultimate goal is to help scientists speed up the investigation of excitable cells,” Gradinaru said. “Then we’ll be able to gain further understanding into diseases like Parkinson’s.”



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