SINGLE FIBRE ANALYSIS OF INHIBITION AND THE POLARITY OF THE RETINAL ELEMENTS

Abstract

Single fiber responses have been isolated from the nasal region of the cat''s retina with the micro-electrode technique and tested by illumination and polarization of the retina between fixed electrodes. The pure on-elements respond to threshold cathodal polarization with an off-effect. An increase of current strength by some 30% elicits a threshold anodal off-effect. The pure off-elements (inhibited by light) have opposite polarity. They respond to cathodal polarization at the threshold with an off-effect, to anodal stimulation of the same strength with an on-effect (not elicitable by light). The on-off-elements are either "cathodal" or "anodal," depending upon their off/on ratio as detd. by illumination at threshold strength. They are held to be combinations of on-paths and off-paths. The results form the basis of a simple explanation of the nature of inhibition in the retina in terms of the horizontal and amacrine cells.