Physiological and morphological identification of L- and C-type S-potentials in the turtle retina

We have recorded the electrical responses to red light and simultaneously marked with procion yellow the cells that give the L- and C-type of S-potential in the turtle retina. The L-type response originates in a horizontal cell with predominantly thick dendrites. The C-type response originates in a horizontal cell with predominantly thin dendrites which are located sclered to those of the L-type response cell. The L- and C-type cells as seen in procion-yellow marking are compared with cells of toluidine-blue stained sections.