(A) Example traces of simultaneously recorded A1 whisker position (θA1, top black trace), A2 whisker position (θA2, bottom black trace) and supraorbital vibrissa position (θSO, blue; gray lines: fully retracted phase of A1). Whisks by A1 that were not matched by whisks of SO vibrissa (missed whisks) are marked by blue arrows. (B) Histogram of ratio of SO vibrissa amplitude (θamp,SO) over A1 whisker amplitude (θamp,A1) for whisking periods (330,085 frames) in the example recording in (A). Ratios above 1.2 are not shown for clarity (0.09% of frames). The peak with ratio near zero, indicated by blue arrow, indicates a substantial fraction of missed whisks in this example recording. (C) Same as (B) but for A2 vs A1 whiskers. There is no histogram peak indicative of missed whisks (0.16% of values are above the axis limit of 1.2). (D) Example traces of θC1 and θC2 (black traces) and θG (red). Missed whisks by the genal vibrissa are marked by red arrows. (E) Histogram of ratio of genal vibrissa amplitude (θamp,G) versus C1 whisker amplitude (θamp,C1) for whisking periods (96,429 frames) in the example recording in (D). Ratios above 1.2 not shown (0.36% of frames). Missed whisks are indicated by red arrow. (F) Same as (E) but for C2 vs C1 whiskers (0.75% of values above axis limit). (G) Diagram of facial nerve innervation of whisking muscles in mouse, adapted from Dörfl, 1985. Motor nerve lesions were performed by cutting the facial nerve (FN) sequentially at the buccolabialis branch (b), which innervates the mystacial pad whisking muscles, followed by cutting at the junction of the temporalis (t) and zygomatico-orbitalis (z) branches (cuts approximately at dashed lines). Whisker and non-mystacial vibrissa movement was measured before and after each cut. (H) Left, example frame capturing movement of left side SO vibrissae, left side A-row whiskers, and right side C-row whiskers. Right, example frame capturing movement of left side G vibrissa, left side C-row whiskers, and right side C-row whiskers. (I) Left, example 1.5 s trace of SO angle (θSO, blue), left whisker (θL, black, middle), and right whisker (θR, black, top) before nerve cut. Middle, same as left, but after left buccolabialis nerve cut. Left whisker movement was abolished, but SO movement persisted. Right, same as middle, but after left temporalis/zygomatico-orbitalis nerve cut. SO movement was abolished. (J) Left, same as (I), but for G angle (θG, red) before nerve cut. Right, same as left, but after buccolabialis cut. G movement was mostly abolished. (K) Summary of nerve cut results, reproduced for convenience from Figure 4G.