Experimental design. On the first day, neural activities during listening to metronome sounds for 6 min were measured using magnetoencephalography (MEG) (first MEG session). Thereafter, two-back task trials were performed for 60 min (conditioning session), in which metronome sounds were started 30 min after the start of the task trials, so that the fatigue sensation was conditioned against the metronome sounds (conditioned stimuli). On the second day, neural activities while listening to the metronome sound for 6 min were measured using MEG to evaluate the effect of conditioning of the fatigue sensation acquired on the first day on neural responses (second MEG session). The metronome sounds were same across all sessions.