Vernon Mountcastle, of Johns Hopkins, is awarded the National Medal of Science by President Ronald Reagan in 1986. Dr. Mountcastle, a leader in neuroscience, died Jan. 11 at 96. (John McDonnell/The Washington Post)

Vernon B. Mountcastle, the first person to understand and describe how the cells in the higher regions of the brain are organized and who was once dubbed “the Jacques Cousteau of the cortex,” died Jan. 11 at his home in Baltimore. He was 96.

A neurosurgeon by training, Dr. Mountcastle switched to physiology research shortly after serving in World War II and spent his entire career at Johns Hopkins University, which announced the death. The cause was complications from the flu, according to the university.

Widely considered the father of neuroscience, Dr. Mountcastle received nearly every major award in science, including the Albert Lasker Basic Medical Research Award, the National Medal of Science and the National Academy of Sciences Award in Neuroscience. Only the Nobel Prize eluded Dr. Mountcastle, who was the first president of the Society for Neuroscience, the author of many textbooks and the editor of the Journal of Neurophysiology.

The citation on the Lasker award, which U.S. scientists refer to as the “American Nobel,” called Dr. Mountcastle “the intellectual progenitor of his field.” His understanding of the brain set the standard for all future neuroscience research.

Building on Dr. Mountcastle’s work, David H. Hubel and Torsten N. Wiesel, who both worked closely with the Hopkins scientist early in their careers, shared the 1981 Nobel Prize in Physiology or Medicine (with Roger W. Sperry) for their discovery of how neurons in the retina assemble information about the visual world.

Another former student, Robert LaMotte, who became a professor of anesthesiology and neurobiology at Yale University, referred to his mentor as the “Jacques Cousteau of the cortex.”

Dr. Mountcastle never forgot the eureka moment in 1955 that launched his ascendancy in the field. His discovery of how neurons in the upper cortex are organized into columns had everything to do with how he was recording test results one day on a yellow piece of paper — vertically and in list form.

Suddenly the physiologist saw in front of him a visual metaphor for how cells are layered in the brain, with skin cells stacked on top of skin cells, motor cells on top of motor cells, and so on. At the time, this contradicted the accepted science of the day, that brain cells were organized in layers by function.

Dr. Mountcastle’s theory was so controversial that when the paper describing the results of the experiment came out in 1957, he was the sole author. Two other researchers declined to have their names attached to the article lest it hurt their careers, he once wrote.

The late brain researcher Steve Hsiao, a former student of Dr. Mountcastle’s, once said he considered himself one of Dr. Mountcastle’s scientific grandchildren and that whenever he met a new class of students, he would hand them Dr. Mountcastle’s 1957 article from the Journal of Neurophysiology and say, “Read this. Everything comes from this paper.”

Vernon Benjamin Mountcastle was born in Shelbyville, Ky., on July 15, 1918, and was the middle of five children. He was 3 when his family moved to Roanoke, Va. His mother, a former teacher, taught him to read by age 4 and, when he started in the public school system, he was immediately promoted two grades.

He graduated from high school at 16 and lived at home while commuting to nearby Roanoke College. Though his mother tried to dissuade him from going to medical school at Johns Hopkins “with all those Yankees” — many in his family had served the Confederacy during the Civil War — Dr. Mountcastle wanted to be a neurosurgeon.

He graduated from Roanoke College in 1938 and received a medical degree from Johns Hopkins in 1942. Until Dr. Mountcastle’s generation, no one in his family had received a college education. His father was a partner in a railroad construction company.

Dr. Mountcastle served in the Navy during World War II and took part in the Anzio and Normandy invasions as a battlefield surgeon. A month after the end of the war, he married a hometown girl, Nancy Pierpont, and a year later was discharged from the military.

Still intent on being a neurosurgeon at Johns Hopkins, Dr. Mountcastle was told he’d have to wait a year for a slot to open. Was he willing to work in a physiology lab until then? Dr. Mountcastle eagerly agreed, and that single decision set him on his life’s course.

“I found no greater thrill in life than to make an original discovery, no matter how small,” he once said.

He taught himself neurophysiology by repeating classical experiments.

His habit in life was to go to work early, come home for dinner and to visit with his wife and three children, then go back to the lab and work until midnight — or later.

“He was a kind of macho guy,” said longtime colleague and neuroscientist Solomon Snyder. “He was used to working through the night, which sometimes you had to do. Once you find the neuron in the monkey you’re looking for, you don’t want to leave the lab.”

Snyder met Dr. Mountcastle in 1966. Fourteen years later, the neuroscience department at Johns Hopkins was formed, and although the older scientist was head of the physiology department at the time, he joined Snyder in the new department.

“He was an extraordinarily powerful intellect, able to incorporate into his work insights in the brain drawn from many different areas,” Snyder said. “He was one of the great giants in neuroscience research.”

The two scientists weren’t just colleagues, they were tennis partners. Snyder regularly played twice a week, and one day in the early 1980s, he noticed his mentor taking a lesson in the same indoor facility. When the two talked afterward, Dr. Mountcastle said, “You know, I haven’t played tennis since college. Someday we should play. . . . I’m not ready yet.”

Four months later, Dr. Mountcastle approached Snyder: “Sol, I’m ready.”

“I’ll never forget that,” said Snyder, who is 76. “I thought, ‘Geez, he’s in his 60s, and he’s going to slow down eventually.’ But each year he got stronger and it got to be, ‘When could I win a game?’ ”

Dr. Mountcastle gave up the game at 80. He also sailed and rode horses and once, in an emergency, had to deliver a colt at the family’s farm, with two grandchildren peering through the stall door.

In addition to his wife, survivors include two children, Vernon B. Mountcastle III of Wallace, N.C., and Anne Mountcastle Bainbridge of Baltimore; a sister, Marguerite Cook of Roanoke; six grandchildren; and two great-grandchildren. A son, George E.P. Mountcastle, died in 1969 in an accidental fall.

After retiring from lab work in 1990, Dr. Mountcastle continued to write and give talks for another 15 years. At that time, he told the Johns Hopkins Medical Magazine that his goal was “to enjoy to the fullest the sunny uplands of old age. Above all, to obey the 11th commandment: Thou shalt not whimper as the darkness falls.”