Haldan Hartline shared the 1967 Nobel Prize in Medicine with Ragner Granit and George Wald"for their discoveries concerning the primary physiological and chemical visual processes in the eye". Haldan Hartline studied the optic nerve of the horseshoe crab that can be separated into single nerve fibers. He found that as the intensity of light increases, the frequency of discharge of nerve impulses increases. The results also showed that the light intensity covered a large range, whereas the stimulated frequency range of discharge was much smaller, compressing the information, and that the initial response is a higher frequency than the steady frequency rate after the nerve fiber adapts to the intensity of light. He then studied the frog’s eye and found that different optic nerve fibers responded differently to the same light. Later he found that illuminated neighboring receptors have reduced firing, inhibiting the amount of light.
