Figure 2.

Low-intensity air puffs, whether unpredicted or fully predictable, do not produce anticipatory facial contractions that could account for changes in tactile sensitivity. A, Average facial EMG aligned on air-puff delivery, as a function of whether the air puff is unpredictable (continuous lines) or fully predictable (dashed lines), for low air-puff intensities (black; subject J.C.: 55% detections for predictable air puffs and 85% for unpredictable air puffs; subject P.M.: 60% detections for predictable air puffs and 60% for unpredictable air puffs), medium air-puff intensities (medium gray; just above threshold air puff, 0.05 bars), and high air-puff intensities (light gray; reported as aversive by subjects, 0.5 bars). B, For comparison, same data as in A reproduced with the same y-scale as facial EMG recordings during five small zygomatic contractions, five large zygomatic contractions, or five voluntary eye blinks. Data for control subject J.C. are presented on the left (plots Ai and Bi) and data for control subject P.M. are presented on the right (plots Aii and Bii).