Train of optostimulations induces PSS. (A1) Raster plots for the spike activity recorded from an MLI during a 1-s-long train of 10 ms light pulses delivered at 50 Hz. (A2) Corresponding PSTH. (B1 and B2) Raster plots and PSTH from the same recording during 1-s-long light pulses. (C) Pooled data (N = 6) on the ratio of spike rate during the stimulation to basal rates, using either continuous light pulse or a 50 Hz train lasting 1 s. The red line shows a fit of the data by a linear function constrained to passing through the origin, with a slope of 0.85. (D) From the same group of cells, pooled data on the ratio of post-stimulation to basal rates. Slope of linear fit, 1.12.