Figure 2.

2P activation of Chronos-expressing interneurons. a, 2P image of a portion of an acute cortical brain slice of a virus-injected mouse. A patched/Alexa Fluor 594-filled (white) interneuron of layer 2/3 expressing Chronos-GFP (green) is photostimulated by a 10 μm holographic spot (red spot). Scale bar, 20 μm. b, c, Representative light-evoked photocurrents (b) and membrane potential depolarization (c) over different illumination powers in a Chronos-expressing interneuron. d, Light-evoked currents in spiking (black) and nonspiking (red) neurons for power densities between 0.05 and 0.12 mW/μm². Each circle corresponds to one cell. e, f, Latencies (e; calculated from the start of the light pulse to the spike depolarization threshold) and jitter (f; calculated as mean deviation of latency) of light-evoked spikes (n = 24 cells) by 10- to 15-μm-diameter spots (data are shown as mean ± SD). Red lines connect data from same cells.