Figure 1.

Experimental paradigm. A, Timeline of the SCT pre- and post-training sessions and the IDT training. First, subjects (n = 65) performed three blocks of the SCT inside the MRI scanner; afterward, subjects underwent a 1-week training in the IDT. Finally, subjects performed the second SCT session. B, IDT. Subjects were presented with two intervals of different durations and had to choose which one was the longest. The first interval was always presented three times. t1 corresponds to the shortest interval, while t2 refers to the longest interval. Intervals were chosen randomly across trials. The base interval was 850 ms, while the comparison intervals were selected from a list of four shorter and four longer intervals with respect to the base interval. C, SCT. A visual metronome (gray square) was presented in the middle of a black screen with an interstimulus interval of 850 ms. Subjects had to synchronize to the metronome, pressing a button for 9 taps, after which they had to continue pressing the button for 12 taps. Feedback was provided as the mean ITI generated for both epochs. Subjects were instructed to accurately produce intervals of 850 ms.