If you work in neuroscience, or follow the field, you probably know who Karl Deisseroth is. At the very least, you’re familiar with his methods. He’s best known for his development of optogenetics, a technique that enables researchers to manipulate individual neurons with light. Today, Deisseroth estimates the technique, which is only about a decade old, is being used in more than a thousand laboratories around the world.

Photo Credit: Ramin Rahimian/Getty via Nature’s 2013 profile of Deisseroth

His other major contribution to neuroscience, which his team announced back in 2013, is called CLARITY. The method renders brain tissues completely transparent while leaving them structurally intact. Thomas Insel, the director of the National Institute of Mental Health has called CLARITY “probably one of the most important advances for doing neuroanatomy in decades.”

Suffice it to say, at 43 years of age, Deisseroth has already secured his position as one of the most influential scientists of this or any other century. John Colapinto’s profile of Deisseroth, which appears in the May 18th issue of The New Yorker, captures not only the prodigious extent of that influence, but the quiet genius from which it springs.

The Stanford neuroscientist Rob Malenka, who oversaw Deisseroth’s postdoctoral work, told me that in some ways he underestimated his trainee. “I knew he was really smart. I didn’t appreciate that underneath that laid-back, almost surfer-dude kind of persona is this intense creative and intellectual drive, this intense passion for discovery. He almost hides it by his presentation.”

Dressed in his usual T-shirt, jeans, and scuffed leather jacket, driving around campus in a dented gray Chevy pickup, Deisseroth could be mistaken for a slightly shambolic creative-writing professor. His initial dream, in fact, was to write. He took writing courses as an undergraduate, and when he was a graduate student in both medicine and neuroscience at Stanford he took a fiction-writing class that met two nights a week at a junior college nearby. He remains an avid reader of fiction and poetry, and he is polishing a book of short stories and essays loosely inspired by Primo Levi’s “The Periodic Table.” Deisseroth says that he perceives a connection between scientific inquiry and creative writing: “In writing, it’s seeing the truth—trying to get to the heart of things with words and images and ideas. And sometimes you have to try to find unusual ways of getting to it.” His fiction bears little resemblance to the technical prose of his neuroscience papers. In a short story describing his first encounter with a schizoaffective patient as a medical intern, Deisseroth wrote that the man’s disordered speech was “Finnegans Wake on the psych ward,” a “soliloquy of suffering” that evoked “science and art together, not in parallel but as actually the same idea, fused, as if I were hearing a Gerard Manley Hopkins poem on neurobiology.”

One morning, when I was scheduled to meet Deisseroth in Palo Alto, I found him standing at the curb with an elderly motorist who had just added a fresh dent to the back of Deisseroth’s truck. The man was agitated. After unhurriedly talking him into a state of calm, then exchanging phone numbers, Deisseroth climbed into the driver’s seat, nudged aside some teething rings (he has three children under the age of six, along with an eighteen-year-old son from an earlier marriage), and asked if I’d slept well. He seemed to have put the accident entirely behind him—even though it had made him late for an important meeting. Many people, I said, would still be discombobulated. “Like those poker players who have a bad hand at the beginning of the night and can’t get back on track?” he said, with a smile. “They call it being ‘on tilt.’”

Deisseroth seems never to be on tilt. He attributes this partly to his psychiatric training: “Those nights on call where there are five emergencies, you’ve got a patient in restraints in the E.R., where they need you immediately, patients up on the psychiatry floor, where someone punched a nurse—you develop a little bit of a ‘just get through it one thing at a time.’ ” His unusual calm has allowed him to compartmentalize competing demands (fatherhood, marriage, neuroscience, literary endeavors, clinical psychiatry, speaking appearances at dozens of conferences a year), so that he can think through complex problems. He told me that, while many people find that walking or jogging shakes ideas loose from the subconscious, he needs to quell all physical activity. “Otherwise, I get this disruption from the motor cortex,” he said. “I have to be totally still.” Ideas come floating up “like a bubble in liquid.” At that point, he goes into an excitable motor state, pacing or scribbling down ideas.

His wife, Michelle Monje—a neuroscientist who specializes in pediatric brain cancer—has seen the process in action often. “He had this idea of controlling specific brain cells years before actually being able to accomplish it,” she says. “It was so out there. Like, ‘Yeah, that would be great—if it worked.’ ”


Read the rest at The New Yorker.

Contact the author at rtgonzalez@io9.com.