Figure 6. Electrically stimulated action potentials become shorter and smaller in amplitude during low-intensity green pulses delivered to NRVMs expressing eNpHR3.0.

(a) Effects of variable intensity green pulses (top). Electrical stimuli (bottom). Reference ‘pre-pulse’ response (black asterisk) is electrically paced. Higher intensity green pulses (first two) silence action potentials. Lower intensity pulse (green asterisk) yields a short duration and smaller amplitude action potential. Anode-break-like response (red asterisk). Post-green pulse (blue asterisk) shows return to control. (b) Closer view of control (black asterisk) compared to low intensity green-pulse action potential (green asterisk). (c) APD metrics (mean ± sem, n = 12 channels from single coverslip), confirming APD shortening by low intensity green-light pulses (green asterisk). Green pulse APD (green asterisk) calculated at APD₈₀ of control ((b), red dashed line) without normalization. Statistical significance computed via 1-way ANOVA with Tukey-Kramer multicomparison criterion, with * signifying p < 0.01. n.s. signifies p > 0.25.