Fig. 3: Using Neuropixels Opto to record and activate local neural populations.

a, We inserted a Neuropixels Opto probe ~1.4 mm deep in the visual cortex of mice expressing the red-sensitive opsin ChRmine (conjugated with mScarlet) in cortical neurons under the CaMK2 promoter. Mice viewed a visual stimulus and an additional red laser illuminated the surface of the posterior cortex. b, Simultaneous Neuropixels Opto recordings and optical stimulation with an example emitter (11), obtained with no visual stimulus (gray screen) and no surface laser. c, Average spike waveforms from five example single units recorded on sites near emitter 11. The mean waveform was calculated across 100 spikes. d, Average firing rate (bin size 50 µm × 2 ms, 40 trials) for the same recording session, plotted as a function of depth, in response to visual stimulation and surface illumination. The color scale bar is shown to the bottom right. e, Responses of the same neurons to single emitter activations at different depths (arrows). f, Summary of these data showing the average over time of response during stimulation with visual stimulus, surface laser and single emitters (abscissa) at different cortical depths (ordinate). g,h, Same format, but for example insertions in two other mice. In different insertions, the emitters were at different cortical depths. In h, the top emitter was outside the cortex (negative depth), where it elicited no activity. Additional measurements in these mice are shown in Extended Data Fig. 5.