125 Stanford Stories

NO. 65
Innovation

Illuminating the brain: Karl Deisseroth

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A technique called CLARITY, developed by bioengineering Professor Karl Deisseroth, renders the brain entirely clear.
Image courtesy of Karl Deisseroth
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In 2015, Karl Deisseroth, a professor of bioengineering and of psychiatry and behavioral sciences at Stanford, received a $3 million Breakthrough Prize for his contributions to optogenetics.
Saul Bromberger and Sandra Hoover
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In optogenetics, genes for light-sensitive proteins are inserted into specific nerve cells of laboratory animals. The proteins activate or inhibit nerve signals when they detect pulses of laser light via an optical fiber implanted in the animal’s brain.
Image courtesy Karl Deisseroth

Stanford bioengineer uniquely reveals the brain’s connections

As a psychiatrist, Karl Deisseroth is troubled by the imprecision of many current treatments for mental illness. As a bioengineer, Deisseroth works to create more precise tools.

The field he pioneered, optogenetics, confronts a core problem long faced by brain researchers – their inability to map or control brain activity in sufficiently minute detail. Optogenetics uses light to control neural physiology and behavior in living brains by introducing light-sensitive proteins into individual nerve cells.

Another technique Deisseroth developed, CLARITY, allows scientists for the first time to map all the connections within the brain and explore how that wiring goes awry in disease states.

In 2015, Deisseroth, a professor of bioengineering and of psychiatry and behavioral sciences at Stanford, received a $3 million Breakthrough Prize for his contributions to optogenetics. It is the latest in a string of honors recognizing Deisseroth’s work toward illuminating some of humanity’s most baffling ailments – autism, intractable depression, schizophrenia.

“The suffering of the mentally ill and the mysteries of the brain are so deep that, to make progress, we need to take big risks and blind leaps,” Deisseroth said on receiving the award. “The members of my lab have taken a leap: borrowing genes from microbes to control the brain.”

In optogenetics, researchers insert genes for light-sensitive proteins into specific nerve cells of laboratory animals. Those proteins either activate or inhibit nerve signals when they detect pulses of laser light transmitted by an optical fiber implanted in the animal’s brain. Scientists observe the effects on the animal’s behavior and deduce the role played by particular nerve cells, relays and circuits.

Deisseroth explains optogenetics in this video.

In this video, he explains how CLARITY renders a brain entirely clear.