Figure 9. Depolarization of bipolar cells during sensitization.

(A) Top, stimulus consisting of biphasic flashes that changed from high (100 %, black) to low (7 %, blue) contrast. The low contrast stimulus was composed of 9 randomly interleaved intensity flashes. Inset shows transition from high to low contrast, colors indicate different flash amplitudes. Each flash amplitude was repeated a total of 3 times at each time point. Bottom, average response of a bipolar cell. (B) Change in membrane potential between L_early (0.8 – 3.2 s after high contrast) and L_late (12 – 16 s after high contrast) at each flash amplitude averaged over bipolar cells that showed an afterdepolarization (n = 4 cells) or afterhyperpolarization (n = 3 cells) following high contrast. (C) Average response of a ganglion cell simultaneously recorded with the bipolar cell from (A) to a low contrast flash while a +500 pA or −500 pA pulse was injected into the bipolar cell. (D) Changes in the firing rate of all simultaneously recorded adapting Off (n = 4) and sensitizing (n = 6) ganglion cells within 0.2 mm of bipolar cells that showed an afterdepolarization.