Fig. 2: Photostimulation response increases with pulse count.

a Volumetric two-photon imaging. Left, three planes (800-by-800 μm, 60 μm inter-plane distance) imaged simultaneously at 7 Hz; right, example plane with example opsin-expressing (magenta) and opsin non-expressing (green) neurons. b Photostimulation-evoked ΔF/F traces for 4 neurons across 10 consecutive trials. Vertical bars indicate stimulation epochs. Trial outcome indicates whether the animal made a correct (check) or incorrect (cross) behavioral response. Inset, proposed flow of activity from opsin-expressing to opsin non-expressing neurons. c ΔF/F traces for the 4 neurons in b showing mean response to each pulse count over a single session. Grey, individual trials; color, mean. d Response amplitudes (z-scored ΔF/F) of all opsin-expressing and opsin non-expressing neurons from one animal sorted by responses to the 9 pulse stimulus. e Spatial map of neural responses from one imaging plane. Size of dot indicates either response amplitude (top) or response probability (bottom) to 1, 5, or 9 stimulus pulses. f Fraction of neurons responsive to stimulation as a function of pulse count. Left, example animal (n = 624 opsin-expressing neurons, n = 2640 opsin non-expressing neurons; box plot denotes quartiles, whiskers denote 1^st and 99^th percentiles, horizontal line denotes median); right, all animals (small dot, median across all full intensity discrimination task sessions; large dot, grand mean; error bars, s.e.m.). g Same as f for response amplitude as a function of pulse count. h Same as f for response probability as a function of pulse count.