HIS FINALIST PROJECT: Studying the genetics of the Arizona cypress tree

What led to the project: After Patrick saw Jaws when he was about five years old, he wouldn't take a bath. In fact, "I wouldn't put my face in the water to wash it for several days after that," he remembers. To work through his fears, he started working his way through his Chula Vista, Calif., elementary school library's section on sharks and—in the process—became fascinated by how living organisms work.

Building on that fascination, in high school a science teacher arranged for him to work with biologist Dave Truesdale at San Diego State University to analyze seeds from the Arizona cypress. Purdon and Truesdale measured the outcrossing rate—that is, a measure of how similar individuals from different populations of the same species are. In general, conifers like the cypress tend to have a high outcrossing rate, but the Arizona cypress turned out to have a relatively low one. That suggests the habitat for the species was shrinking, possibly the result of "human population encroaching on its habitat and wildfires," Purdon says. He entered the results in the 1992 Westinghouse Science Talent Search and was named a finalist.

The effect on his career: The Westinghouse nod was "rewarding for my family—we come from a pretty humble background," he says. His stepfather, who had enlisted in the Navy, and his homemaker mother had spent many hours driving him to and from science fairs and S.D.S.U. The scholarship money made that a worthwhile investment. Purdon was dazzled by the other finalists; he told his shark story and another student mentioned calling up a local aquarium and arranging to dive with the sharks to learn about marine biology. "That hadn't occurred to me—how doors would open to you as a result of your own initiative," he says.

He went to Harvard University to study engineering, graduating in 1996, then later to the Massachusetts Institute of Technology for biomedical engineering, earning his doctorate in 2005.

What he's doing now: As Purdon was wandering around M.I.T. one spring day a few years ago, looking for an excuse not to work, a classmate mentioned that he planned to attend a talk by neuroscientist Christof Koch on consciousness. At the end, Koch mentioned that anesthesia was one of the big question marks in the field. Anesthesiologists "cause loss of consciousness every day and have no idea how it works," Purdon says. But they do know how to control it precisely—and because of that, Purdon thought that anesthesia might be a great tool for studying consciousness.

He went back to the lab immediately afterward and made plans to study images of anesthetized people's brains. He's been working on this question for several years now, discovering that "there's a lot going on in the brain after you've lost consciousness under anesthesia." He was appointed an instructor in anesthesia at Harvard Medical School, and currently does research at Massachusetts General Hospital. "General anesthesia is one of the biggest mysteries of modern medicine," says Emery Brown, a professor of anesthesia at Harvard Medical School and Purdon's faculty mentor. Purdon's work has "major significance," because it will help us understand how activity in different areas of the brain changes under anesthesia. "This new knowledge will help us design better, safer anesthesia drugs that can reduce morbidity and unwanted side effects by targeting only those areas that are needed to induce general anesthesia and leaving other areas untouched," he says. "These new insights will also help us design better monitoring devices to follow brain activity when patients are under general anesthesia."

Purdon has been widely published. If you Google "Patrick Purdon," however, his anesthesiology and imaging studies are not the first links that come up. Instead, you meet Patrick Purdon, the jazz singer, who performs all over the Boston area. A roommate in college had been in a jazz band, and Purdon found himself drawn to the music. "There's something very democratic and egalitarian about it," he says. "Every instrument has a chance to be the soloist, yet you're working together as a team."

He didn't have much of a musical background, but he took voice lessons during graduate school and practiced a lot. Jazz was pushed to the back burner as he was finishing his PhD, but on graduation weekend—it was "literally a dark and stormy night," he recalls—he found himself at an area music venue, Lucky's Lounge, talking with pianist Al Vega. Vega told him to come hear the sets at another jazz spot, Remington's, on Wednesday. It turned out to be a competition. Purdon wasn't sure he wanted to enter, but finally he got up the nerve. "I hadn't sung a note in two years but it was like putting on old comfortable shoes," he says. He wound up winning—and now performs every chance he gets.