Figure 1.

For each subject, 3 runs were performed that consisted of 40 consecutive trials of a visual/emotional task. Each trial comprised 5 s during which a fixation cross was shown, 5 s during which a picture was displayed, and an additional 2 s during which subjects could respond and indicate their judgment of the picture's emotional valence (positive/neutral/negative) with 1 of 3 button options. Sparse fMRI acquisitions took place during the last 2-s interval only; in the interspersed 10-s periods of scanner inactivity, tone sequences were presented. Within a trial, the fundamental frequency (¼, ½, 1, 2, 4, or 8 kHz) and loudness (soft or loud, differing by 20 dB) of the tones remained the same, but these conditions (plus a silent condition) were varied across trials in a random fashion unrelated to the task.