FURTHER STUDY ON THE ORIGIN OF THE SO-CALLEDCONE ACTION POTENTIAL (S-POTENTIAL).ITS HISTOLOGICAL DETERMINATION

Abstract

1. The origin of the so-called cone action potential (S-potential) was studied histologically on the retina of Cyprinus auratus. After insertion of a superfine micropipette filled with 10% potassium ferricyanide to a depth where the S-potential was maximal in amplitude, ferricyanide ions were injected electro-phoretically to make react with ferrous ions diffusing in from the retinal surface and produce a stain of Turnbull's blue around the tip of electrode.
2. Examination on serial sections of such materials led to the conclusion that the optimal depth for recording the S-potential is around the border of inner plexiform and inner nuclear layer, ranging from a distal half of the former to proximal half of the latter. The result was discussed in the con-nection with some earlier observations.
3. Impulse discharges were detectable only from a depth about 50μ more proximal to the origin of S-potentials. Histologically, this depth corresponded to the layer of the ganglion cells.