David Hubel was a Nobel Prize-winning neuroscientist whose astonishing map of the visual cortex pulled back the curtain on one of the brain's most mysterious functions, the power of sight. Starting in the late 1950s, Hubel's research revealed the architecture of the visual cortex, the region of the brain that receives floods of data gathered by the eyes.
Together with the Swedish neurophysiologist Torsten Wiesel, he discovered how nerve cells – neurons – analyse the light rays that hit our retinas, bit by bit, to assemble the detailedimages that we perceive as our external world. Over 25 years, the pair found that the cortex is arranged in vertical columns of cells, each module devoted to process a different constituent of the seen world: form, contour, colour, movement and three-dimensionality.
For their collaboration, begun at Johns Hopkins University and continued for the next two decades at Harvard, Hubel and Wiesel won the 1981 Nobel Prize in Physiology or Medicine. They shared the prize with Roger Sperry, then affiliated with the California Institute of Technology.
When they began studying the visual system, little was known about the functional organisation of the cerebral cortex, and scientists had only recently begun recording electrical impulses from that area of the brain. The Nobel Prize committee cited the two men's research as having "disclosed one of the most well-guarded secrets of the brain: the way by which its cells decode the message which the brain receives from the eyes."
In their first experiments together in 1958, Hubel and Wiesel, an inquisitive and often mischievous pair, crammed a projector inside their 15-by-15-foot laboratory at Johns Hopkins and sat their research cats, adorned in electrical headgear, before a screen. They displayed spots of all sizes before the animals – dark spots on bright backgrounds and bright spots on dark – trying to find a stimulus that could coax a single neuron, wired to a surgically implanted electrode, to fire.
For the first few days they got no response. Desperate, they danced in front of the cats waving their arms. At one point, mostly as a joke, they presented the cats with pictures of beautiful women in magazine advertisements. In their 2004 memoir, Brain and Visual Perception: The Story of a 25-Year Collaboration, they wrote that "our room must have seemed like a circus, complete with a tent and exotic animals."
It was a shadow created when Hubel and Wiesel were rearranging their equipment – a faint line that swept across the projector screen in one specific orientation – that made a cat's neuron fire. It was a serendipitous first step in a career-long journey of understanding the visual system; Hubel recalled that they studied this first cat neuron for nine hours. Their seminal 1959 publication of these findings, they wrote, "of course gives no hint of our struggle. As usual in science reports we presented the bare results, with little of the sense of excitement or fun."
Other lines of Hubel and Wiesel's work led to the discovery that visual cells begin developing immediately after birth and degenerate quickly if they aren't used. That finding led to a change in the established protocol of delaying operations to correct visual impairments in children.
He was born in 1926 in Ontario to American parents and raised in Montreal. His father was a chemical engineer, and the Hubel developed an interest in science as a child. He used his chemistry set to fire toy cannons, built radios and sent off hydrogen balloons into the Canadian countryside with attached notes, one of which, he recalled, "brought an answer, after many months, in French, from a farmer's daughter 100 miles away."
At McGill University in Montreal he graduated with honours in mathematics and physics in 1947. Though accepted to graduate school for physics, he applied to McGill's medical school on a whim. He recalled in the memoir: "to my horror I was accepted there, too."
He enrolled having taken only one biology class, a summer course on invertebrate zoology and botany, and graduated in 1951. During his medical internship he met his future wife, Ruth Izzard, at the university choral society, where they sang together.
After serving in the Army Hubel joined Johns Hopkins to continue research with Vernon Mountcastle, one of the leading neurophysiologists of the era. Mountcastle's lab was undergoing a six-month-long renovation andand Stephen Kuffler, a neurophysiologist who studied vision, invited him to team up with Wiesel, who had just arrived from Sweden. The partnership that was slated for half a year lasted for 25.
Once, Hubel recalled, Mountcastle asked how many visual cells the men had studied – he had just published a paper compiling observations of some 600 neurons. "To us, that was an astronomical number," Hubel wrote. He answered that they were studying cells No 3,006, 3,007 and 3,008. "In order to catapult ourselves into a league that came close to Vernon's we had begun our series of cells with No 3000. But we did not tell Vernon."
Hubel and Wiesel moved with the Kuffler team to Harvard Medical School in 1959, where they formed the core of Harvard's neurobiology department, the first of its kind in the US. There, Hubel continued research and lecturing for the next four decades. His favourite course was his seminar for first-year undergraduates, which he taught for more than a decade, even after he officially retired. Each year, he would accept a dozen Harvard freshmen into his lab, leading them through dissections of sheep brains, practising surgical sutures on pieces of scrap leather and teaching them how to weld and build their own simple electronic gadgets.
Outside academia, Hubel, who died of kidney failure, learned Japanese and French and studied astronomy. He was also a pianist and flautist. His interest in photography led to a friendship with Edwin Land, a co-founder of Polaroid.
Alyssa A Botelho, Washington Post
David Hunter Hubel, neuroscientist: born Windsor, Ontario 27 February 1926; married 1953 Ruth Izzard (died 2013; three sons); Nobel Prize 1981; died Lincoln, Massachusetts 22 September 2013.