Haldan Keffer Hartline
The Nobel Prize in Physiology or Medicine 1967
Born: 22 December 1903, Bloomsburg, PA, USA
Died: 17 March 1983, Fallston, MD, USA
Affiliation at the time of the award: Rockefeller University, New York, NY, USA
Prize motivation: "for their discoveries concerning the primary physiological and chemical visual processes in the eye."
Prize share: 1/3
Our vision functions because light from the surrounding world is captured by many light-sensitive cells in the retina at the back of the eye. A series of reconnections and transformations of chemical and electrical signals finally result in visual impressions. In studies of the horseshoe crab around 1950, Keffer Hartline analyzed how the primary signals from visual cells are processed in a network of nerve cells. Among other things, he showed that when a cell is stimulated, signals from surrounding cells are suppressed. This makes it easier to understand the concept of contrasts.