a, Average whisking activity of a vIRtPV-ChRmine-GFE3 mouse, showing the mean of the pixel intensity difference between each consecutive video frame. Blue to red color scale: low to high activity. In contrast to the ipsilateral (GFE3) side, contralateral whisking is highly active across the whole whisking range. b, Increased firing, but no rhythmic activity at whisking initiation for a opto-tagged vIRtPV-ChRmine-GFE3 unit (whisking initiation time determined from contralateral C2 vibrissa). c, Whisking phase tuning of all opto-tagged vIRtPV-ChRmine-GFE3 single units (conventions as in Fig. 2 and 4).