Figure 1. Chronic electromyographic recordings of the diaphragm to monitor inspiration in freely moving mice.

(A, B) Schematics of the EMG recording electrodes and of the diaphragm implantation. (C) Simultaneous diaphragm EMG recordings (raw and integrated traces in black) and whole-body plethysmography (WBP, volume and flow, in blue) showing that the diaphragm neurogram estimates inspiratory flow. (D) Enlarged view of three inspiratory bursts highlighting the following respiratory parameters: inspiratory time (Ti) defined as a bout of diaphragm activity, and expiratory time (Te) as the silent period between bouts. (E) Diaphragm activity recorded on the day of the surgery (J0) and at 7, 10, and 28 days post-surgery (representative of four mice). (F) Raw and integrated diaphragm neurograms in an open field test during rest, grooming and spontaneous running showing preserved recording quality in spite of movements. (G) Locomotor trajectories of one representative non-implanted mouse (gray) and one representative EMG-implanted mouse (purple) for 10 min in the open field. (H) Bar-graphs showing the mean ± SD mobility rate, locomotor speed during mobility and total distance traveled in control (n = 5) and EMG-implanted mice (n = 4). p values in (H) are obtained from Mann-Whitney U tests and considered not significant when p>0.05.