Neural Substrates of Inter

ire ent in the absence of practice with the right hand. fMRI Measurements presses each (120 key presses per block). The inter-epoch interval for the task condition was constant at 60 s. In the rest condition, sub-jects were asked to remain awake and not move. A total of 305 func-tional images were acquired on each fMRI run. Each block shown in Figure 1A contained a total of 120 key presses. The order of keys in the training sequence was 4-2-3-1-1-3-2-1-3-4-2-4 and in the con-termsRight-hand sequence learning. Random-effect analysis showed that, consistent with previous results [S7–e left ition 1 er, po-total, ing M1 (BA4), postcentral somatosensory areas (BA1, 2 and 3), dorsal premotor cortex (PMd, dorsolateral BA6), subjects performed ten repetitions of a 12-item sequence for a total of 120 key presses per block. In the random blocks, the asteriskS12], practice of the training sequence with the right hand was associated with significant bilateral increases in activity relative to rest in several brain regions, includ-trol sequence was 1-3-3-4-2-1-3-2-4-1-4-2, as expressed in of asterisk and key locations. The asterisk positioned at th end of the screen corresponded to position 1 (in which pos corresponded to the index finger, position 2 to themiddle fing sition 3 to the ring finger, and position 4 to the little finger). Ining-dependent improvement in RT in the transfer hand (Figure 2A, dashed line between white bars) is not pres-14 ms and 318 6 15 ms, respectively; Paired t test, p = 0.46; Figure S1). These results indicate that the train-were instructed to respond to the visual cues as quickly and accu-rately as possible. Each block contained two epochs of 60 keySupplemental Dat