Three functional scans of olfactory stimulation per subject-session were performed (24 odor events in each of the three stimulus classes of AO, ApCO and NApO plus 42 odorless control events). No images were presented during imaging, and subjects underwent olfactory stimulation with eyes closed. Subjects reported the presence (button 1) or absence (button 2) of an odorant on a response box, but were not asked to identify the odorants.
