A, effect of light pulse duration on overall efficacy of the optogenetic approach (n = 48 points per pulse duration, P < 0.0001, Friedman's test). Each point shows the total percentage of successful optogenetic AT termination attempts (i.e. rapid + delayed success rates) for one optrode configuration in one patient model. B and C, effect of illumination strategy (i.e. distributed optrode grids of different density (n = 15): D‐64, D‐128, D‐128; spatially targeted (n = 3): ST) on efficacy of the optogenetic approach for 100 ms‐long light pulses (B: P = 0.01, Kruskal–Wallis test) and 1000 ms‐long light pulses (C: P = 0.04). [Color figure can be viewed at wileyonlinelibrary.com]