Through much of the 20th century, scientists believed the brain could develop new connections, but only early in life. By early adulthood, development was over and the brain and its circuitry remained relatively fixed. Doctors reserved brain surgery, as shown here at the Sorbonne in Paris, for only the most grave and traumatic of injuries. Doctors assumed that patients with less severe injuries couldn’t really benefit from extensive treatment or rehabilitation, so they didn’t perform it.

In the 1960s, scientists found that with rigorous rehabilitation, stroke patients could recover far more movement than anyone had thought possible. This, along with key studies on the cat visual system and monkey motor-control regions, suggested that the adult brain could bypass damaged and unused regions. This upended conventional beliefs, and some scientists began to suspect the brain was far more adaptable than most believed.

One of those scientists was Carla Shatz, professor of biology and neurobiology at Stanford University (shown), who shared the 2016 Kavli Prize for Neuroscience with Eve Marder of Brandeis University and Michael Merzenich of University of California, San Francisco. Shatz found that before birth, activity in the human retina sends signals that sculpt the neural circuitry in parts of the brain that make sense of what we see. The fact that neural activity alters brain wiring helps explain the brain’s ability to adapt, and it shaped the modern concept of neuroplasticity.