Fig. 2.

Examples of responses of individual RVM neurons initially classified as ON cells (A) or OFF cells (B) to pinching of the hind paw. Stimuli and the order in which they were applied: tail pinch, hind paw pinch, forepaw pinch, facial skin pinch [temporomandibular joint (TMJ) pinch], gentle stroking of the ocular surface, injection of ATP into the TMJ, and application of capsaicin to the ocular surface. Accompanying EMG activity was recorded from the ipsilateral biceps femoris or the contralateral masseter muscle. Arrows point to responses evoked by stimulation at the site of each arrow's origin. Arrowheads indicate time of chemical application. Horizontal bar above the EMG activity is equal to 5 s. Bin widths for histograms are either 0.5 s or 1 s.