Physiological and morphological identification of horizontal, bipolar and amacrine cells in goldfish retina.

1. Intracellular recordings were made from various types of cells in the isolated goldfish retina, and Procion Yellow was injected from the recording pipette in order to identify histologically the structure recorded. The dye diffused and stained the cell body and processes down to the fine branches.2. S-potentials were identified as coming from the external horizontal cells and from the internal horizontal cells. Both L- and C-type S-potentials were found in both regions, and no histological differences were seen in cells giving these two types of responses. S-potentials recorded from the external horizontal cells showed less spatial summation than those recorded from the internal horizontal cells.3. Bipolar cell responses consisted of sustained potentials associated with an antagonistic centre-surround type receptive field (on-centre, off-surround or vice versa). Spike activity was not observed in bipolar cells.4. Amacrine cells responded with transient depolarization both at the beginning and at the end of illumination. They sometimes showed spike activity. The amplitude of on- and off-depolarization showed slight dependence on stimulus geometry but a distinct centre-surround organization was not observed.