A Triumph for Basic Research

Karl Deisseroth and his colleagues are using light to shed light on some of our most perplexing health issues. Deisseroth, an associate professor of bioengineering and psychiatry at Stanford, described the new technology of optogenetics Thursday evening on the lawn outside the Cantor Arts Center.

His talk, “Using Fiber Optics and Genes from Algae to Solve Problems in Psychiatry,” was part of the Stanford Summer Science Lecture Series. Deisseroth called this blend of bioengineering and psychiatry “a bizarre combination.”

In his practice as a psychiatrist, Deisseroth has encountered chronic and difficult-to-treat disorders, such as PTSD, anxiety, autism and schizophrenia. He pointed out that depression is the leading cause of disability among women aged 18 to 45 worldwide.

Although there are medications available, they often have undesired side effects. And to further complicate things, Deisseroth says, our understanding of the brain is nowhere near as precise as, say, a cardiologist’s understanding of the heart.

Deisseroth looks at the brain as a fundamentally electrical device. It has about 100 billion neurons with about 10,000 connections emanating from each of them. They carry electrical currents in the picoampere range and have millisecond response times.

In 1979, Francis Crick suggested that “what we need is a way to control neurons specifically as they are embedded in intact tissue.” Deisseroth considered the possibility of using light to control the neurons. Light waves penetrate through tissue harmlessly. They come in different colors and can be pulsed in milliseconds.  

Since 2004, Deisseroth’s lab has used light to stimulate light-sensitive proteins of pond scum algae to control neurons in brain tissue. These proteins are called opsins and act as tiny gatekeepers, regulating the flow of charged ions across cell membranes. Positive and negative ions act as switches, and the opsins respond to different colors of light.

Deisseroth coined the term “optogenetics” in 2006 to describe the fusion of optics and genetics to control things like proteins with precision. He said “we use rats and mice in experiments and watch how they interact when we apply light," and, They have the same parts as human brains, just smaller.” 

He told his enthralled audience that he and his colleagues hope to understand what the human brain is doing. "Rodents have the same fears that we have," he said. "They live their lives in a state of heightened anxiety. Valium takes away their fears."  

Although much of his lab’s work is applicable to understanding psychiatric issues such as depression, psychoses, chemical dependency and addictions, as well as neurological ailments, like Parkinson’s disease, Deisseroth reflected that optogenetics “points to the value of doing risky experiments” and voiced a call for continued support of basic research, even in a budget crises.

Deisseroth is not worried that optogenetics could become a weapon leading to control of individuality. He says it’s just a research tool that’s extremely complicated to use and requires willing participants. He said he believes that in the next 20 years, it will lead to “deep insights.”