Figure 1. TeNT causes a botulinum neurotoxin–like flaccid paralysis upon injection in the WP in a model of CT.

(A) The top panel illustrates the experimental setup to video record WP activity in head-fixed mice in a model of CT upon TeNT injection in the WP (1 ng/kg in a final volume of 1 μL) as a model of CT. Mice are held at the center of a mouse arena through a metal bar cemented to the skull; an infrared camera is positioned on top of the mouse snout to record the whisking activity. The bottom panel schematizes the apparatus to measure the compound muscle action potential (CMAP): the green electrode records WP myofibers’ depolarization elicited by facial nerve stimulation through the red electrode; stimulation and signal amplification are controlled with a computer connected via an interface. The central panel shows the time course of a typical experiment for WP video recording and CMAP analysis across TeNT injection in the WP. (B) Representative video frames showing the whisking ability in naive mice and at indicated time points after TeNT inoculation in injected (ipsi) and noninjected (contra) WPs; black arrows and bars indicate the movement ability of the vibrissae as deduced from recorded videos; segments with blunt ends indicate full paralysis. (C) Representative traces of CMAP recordings in ipsi and contra WP (top) and their quantification (bottom) at indicated times after TeNT injection. Data are expressed as means ± SD; ***P < 0.001, ****P < 0.0001 assessed by Student’s t test. Black circles indicate the number of animals used in the experiment.