These reversals were highly robust. They were stable, lasting for the duration of the recording (Figure 1; Selleckchem ABT-263 further analyzed below). In addition, they did not depend on the parameters of the grating that were used to assess directional tuning, such as

spatial and temporal frequencies (see Figure S1 available online). Specifically, the reversals occurred when the gratings in the DS test were symmetric (equal black and white phases), asymmetric (black phase of the grating was three times as long as the white phase, Figure 1A; Figure S1), had different speeds (15 or 30 deg/s), or had different spatial frequencies (ranging from 225 μm/cycle to 1,800 μm/cycle). Since we observed cells reversing their directional preference in response to symmetric and asymmetric gratings of different properties, we combined cells subject to different DS tests in our analysis. Since

individual DSGCs had varying responses to the P-N adaptation protocol, we assessed the change in directional preference using two measurements. (1) We classified adapted cells by the change in their PD by calculating the vector sum and the DSI based on the directional tuning that was acquired after the adaptation protocol. We termed the DSI computed using this newly acquired PD DSI∗. If the adapted cell was sharply tuned (i.e., vector GDC-0941 supplier sum magnitude > 0.2 and DSI∗ > 0.3), the newly acquired PD was set to be the direction of the vector sum, and the change in PD was

calculated as the angle difference between this new PD and the original PD. If this difference was less than 90°, the adapted cell was classified as stable (Figures S2A and S2B), and if it was greater than 90°, the adapted cell was classified as reversed (Figures 1 and 2B). If the cell was not sharply tuned after adaptation (i.e., vector sum magnitude < 0.2 or DSI∗ < 0.3), it was classified as ambiguous much (Figure S2C). (2) We quantified the change in response along the original P-N axis. Here the DSI after adaptation was comparing the response to stimulus moving in the original PD and response to stimulus in the original ND (as in Trenholm et al., 2011). This is unlike DSI∗ in which the computation is based on responses to motions in the adapted PD and ND. Thus, reversed cells would exhibit negative DSI values since their response after adaptation to motion in the original PD is lower than their response after adaptation to motion in the original ND. Based on these two measures, we computed the efficacy of the adaptation protocol. The P-N adaptation protocol led to 38% of DSGCs (9 out of 24) showing reversal (Figure 2C, left), 38% (9 out of 24) becoming ambiguous in their directional tuning (i.e., non-DS), and the minority 25% (6 out of 24) remaining stable. Grouping data across all cells, we found that the P-N adaptation protocol led to a significant reduction in the DSI (Figure 2C, right; and Table S1).