The Brain Voyager

> Vernon Mountcastle enjoying “the sunny uplands of old age."

Catching up with "the Jacques Cousteau of the cortex."

More than a half-century has passed, but revered neuroscientist Vernon Mountcastle recalls his most celebrated moment of discovery with perfect precision. It was when he determined that the brain, unlike any other part of the human body, is divided into magnificent little subunits—or columns—each with its own specific role.

On that day in 1955, Mountcastle—who received his M.D. from the School of Medicine in 1942 and went on to direct physiology from 1964 to 1980—was studying the results of tests on the brains of cats, recording the character of each cell from successive penetration layers. “I was writing them down vertically on a yellow piece of paper,” he recalls. Suddenly the vertical notetaking helped him see the stunning pattern in the brain: Skin cells lay atop skin cells, joint cells atop joint cells and so on, extending in columns from the brain’s surface all the way down through six layers of cortex. “That was my ‘aha’ experience,” he says.

Mountcastle’s revelations forever changed his field: Before his breakthrough, researchers had believed that brain cells were organized randomly, with each layer of the cortex having a specific function. The new finding “hit neuro-anatomists where they lived,” says the legendary scientist, now 88 and settled into a townhouse in North Baltimore with his wife of 61 years, Nancy. The pair moved from their 13-acre farm in Monkton, north of Baltimore, in July.

But despite the wealth of accomplishments that have marked one of the finest careers in modern medicine, Mountcastle—snowy-haired and attired in the manner of a country squire (tie and sweater vest)—is not completely at ease talking about them. “I’m a pretty modest fellow,” he says in his soft, Virginia-accented voice. “In fact, I’m a little shy.”

But the record speaks for itself: Mountcastle’s formative discovery of the brain’s arrangement, combined with subsequent breakthrough work on the parietal lobe, earned him the 1983 Albert Lasker Award for Basic Medical Research. The citation on his Lasker—which scientists call “the American Nobel”—called Mountcastle “the intellectual progenitor of his field” and the first researcher to ask, “How does the brain process, perceive and respond to the information gathered by the senses?”

Though his “columnar” discovery is more famous, Mountcastle says he actually takes greater satisfaction in his research on the cortex’s parietal lobe, the region involved in such higher functions as the perception of sensory information and physical reaction to it. These experiments, which he called “the waking monkey technique,” took him five years to perfect. He figured out how to record the activity of a fully alert monkey’s brain as the animal pressed a key in response to such stimuli as moving light beams.

Known today as the father of neuroscience, Mountcastle has received practically every major scientific award, including the National Medal of Science and the National Academy of Sciences Award in Neurosciences. In his 46 years on the faculty, he directed the training and research of more than 49 postdoctoral fellows, dozens of whom have become heads of their own departments.

All of them cite Mountcastle’s phenomenal knowledge, his fiercely focused work ethic, the clarity of his speech and writing, his patience and civility, his devotion to his family and his astounding capacity to handle a multitude of assignments at once, while somehow remaining ever-present in the lab.

Robert LaMotte, now professor of anesthesiology at Yale, who counts Mountcastle as his most influential mentor, worked with Mountcastle as he placed delicate microelectrodes into the brains of research animals. “It was akin to going into a little submarine with him, like being the Jacques Cousteau of the cortex,” LaMotte says.

“I consider myself one of his grandchildren, scientifically,” says Steve Hsiao, associate professor of neuroscience in the Hopkins Mind/Brain Institute, which Mountcastle helped found. “My first day as a graduate student, my mentor Ken Johnson gave me a paper of Vernon’s and said, ‘Read this. Everything comes from this paper.’ Today I tell my students the same thing.”

Mountcastle says that, with every new subject he’s taken on, he’s “swallowed it whole.” And he’s still doing it. In his late 70s, he began working on two monumental scientific monographs, Perceptual Neuroscience: The Cerebral Cortex (Harvard, 1998) and The Sensory Hand: Neural Mechanisms of Somatic Sensation (Harvard, 2005).

Sol Snyder, the distinguished 30-year head of the Department of Neuroscience here and a friend (and former tennis opponent) of Mountcastle’s, says no matter how far today’s studies of the molecular biology of brain cells take researchers in the future, neuroscientists ultimately will be drawn back to Mountcastle’s work. “The more we know of individual genes that regulate brain function, the more it becomes clear that molecular biology is just the beginning—and we need to return to the lessons of Vernon Mountcastle to put it all together.”

Since November 2005, Mountcastle has been “retired for about the third time.” He says he now hopes to attain a goal he first described in 1990: “To enjoy to the fullest the sunny uplands of old age. Above all, to obey the 11th commandment: Thou shall not whimper as the darkness falls.” Having recently endured a slow recovery from a bad case of shingles, Mountcastle concedes with a slight grin: “It’s sometimes hard to not whimper.”

Neil A. Grauer