Percent increase above resting condition in the “point of subjective equality” (PSE) for a probe stimulus applied to the right index finger as compared to a reference stimulus to the left little finger.

<p>A) shows results from experiment 1 for left (grey bars) and right finger movements (black bars), when stimuli were delivered 200, 100 and 50 ms prior to a cue instructing which finger to move or together with movement onset with equiprobable chance of left and right cues. Asterisks indicate highly significant (p<0.001) changes as compared to the baseline (resting) condition (two-tailed t-tests), which only occurred when the right finger was subsequently cued. B) shows results from experiment 1 (left side) and experiment 2 (right side) in which right cues occurred 4 times more frequently than left cues (“80:20”). A highly significant interaction (ANOVA interaction F1,14 = 17.22, ** = p<0.001) arose because attenuation in the right finger occurred also on rare left-cued trials in the 80:20 group only, suggesting a new expectation-based mechanism of sensorimotor attenuation.