Haldan Keffer Hartline

“The retina of Limulus is a convenient preparation for the study of the activity of single photoreceptor units and of the interactions between them.”

“The nervous system, in its processing of the information it receives from the sense organs, is not a passive, inert transmitting system.”

“Indeed, the activity of any one receptor is influenced by that of its neighbors.”

“Mutual inhibition, acting between receptors, serves to enhance contrast at edges and borders of retinal images.”