Figure 2.

Static measurements of jaw tone during application of noxious stimulus under a non-surgical depth of anesthesia. Pressure is shown on the y-axis (range: −500 to 3,000 mmHg across all panels), and time is on the x-axis in seconds (all panels display the 60 s intended for noxious stimulation). The jaw was partially opened using a custom-built device to a stable pressure (~100 mmHg) before application of a noxious stimulus. The noxious stimulus was produced with a 15-cm Doyen forceps applied to a dewclaw and closed to the first ratchet (black arrow) for 60 s or until a limb withdrawal response was observed, whichever came first (white arrow). All pigs had positive limb withdrawal, no pigs had changes in jaw tone leading up to limb withdrawal and only 2 pigs (pig 5 and pig 7) had an abrupt and marked increase in jaw tone concurrently with limb withdrawal.