Figure 3. Motor signals from previous trial affect current trial.

(a) Time-frequency analysis of motor cortex activity contralateral minus ipsilateral to previous trial's button-press in pairs of consecutive trials. Data from previous trial is aligned to button-press. Data from the current trial are aligned to stimulus onset. Data from consecutive trials are concatenated according to median ITI. Z-scores across subjects (n=20). (b) Time-course of beta power (12–30 Hz) in motor cortex contra- and ipsilateral to previous trial's button-press. Activity is normalized by the mean across trials. Shaded areas indicate SEM across participants. Black bar marks a significant difference from 0.7 s after the previous button-press to 4.6 s in the current trial (P=0.002, two-tailed one-sample cluster permutation tests, n=20). (c) Time-course of the difference in beta power contra- and ipsilateral to the previous trial's button-press. (d) Beta power after left minus right button-presses (−1 to 1.25 s). Dashed lines indicate the hand representation of primary motor cortex and the central sulcus, respectively. (e) Beta rebound averaged across the prestimulus period is not significantly different after correct and incorrect choices (P=0.84, two-tailed paired permutation test, n=20).