08/31/2026
When Rockefeller’s H. Keffer Hartline began his research into visual processing in the 1930s, little was known about the retina, where cells convert external stimuli into neural signals. Throughout his long career, he would go on to make astounding discoveries about the complex interplay between the eye and the brain.
Fascinated by how organisms sense light, Hartline was drawn to the horseshoe crab’s relatively simple visual system, which includes long, easy-to-isolate optic nerve fibers and large photoreceptors in the retina. Among his many innovations was developing groundbreaking methods and tools for isolating single optic nerve fibers in the horseshoe crab eye and then measuring each one’s voltage—the first such recordings in history. These experiments proved his hypothesis that visual information is relayed to the brain through nerve impulses.
Later, he discovered the nerve fiber network that links photoreceptor cells as well as a key form of communication between them: lateral inhibition, or the ability of an excited neuron to mute the activity of its neighbors. This mechanism heightens the contrast between light and shadow and gives sharper edges to shapes—a fine tuning that occurs before an image is even sent to the brain.
For these and other fundamental insights, Hartline won a Nobel Prize in 1967.
As famed biophysicist Floyd Ratliff, a long-time Rockefeller collaborator, said, ''Hartline's basic studies on the integrative action of the retina provided the foundation for practically every advance in the neurophysiology of vision.''
Indeed, Rockefeller’s ninth president and current Vincent and Brooke Astor Professor Emeritus, Torsten Wiesel, built directly upon Hartline’s concepts in his own work discovering how the brain interprets nerve signals to construct images.
For that research into visual processing, Wiesel won a Nobel Prize in 1981.
