Experiment timeline.

<p>Training sessions in the MRI scanner during the collection of blood-oxygen-level-dependent (BOLD) signals were interleaved with training sessions at home. Participants first practiced the sequences in the MRI scanner during a baseline training session <i>(top)</i>. Following every approximately 10 training sessions (see <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1003171#pcbi.1003171.s009" target="_blank">Table S1</a>), participants returned for another scanning session. During each scanning session, a participant practiced each sequence for 50 trials. Participants trained at home between the scanning sessions <i>(bottom)</i>. During each home training session, participants practiced the sequences in a random order. (We determined a random order using the Mersenne Twister algorithm of Nishimura and Matsumoto <a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1003171#pcbi.1003171-Matsumoto1" target="_blank">[101]</a> as implemented in the random number generator rand.m of Matlab version 7.1). Each EXT sequence was practiced for 64 trials, each MOD sequence was practiced for 10 trials, and each MIN sequence was practiced for 1 trial.