[A] Schematic illustration of the four experimental phases. For details see the Methods section. [B] Schematic illustration of clustered temporal acquisition (CTA) as implemented in the present study. In each single trial the hemodynamic response is obtained from three consecutive volume scans (Tacq 1 s). The interval between onset of one volume triplet and onset of the subsequent triplet is 12 s. The interval between onset of stimulus presentation and data collection varies between 3 and 5 sec and allows enhanced sampling of data points relative to single volume acquisition. This approach precludes confounding hemodynamic responses to stimuli with scanner noise.