Three whole-brain BOLD contrast sensitive functional imaging scans were conducted on a Siemens 3T Magnetom Trio scanner (Erlangen, Germany). A whole-brain high resolution anatomical image volume (1.0×1.0×1.2 mm voxels) was first collected using a 3D magnetization prepared rapid gradient echo (MPRAGE) sequence for anatomic registration of the functional images. For each functional scan, BOLD volumes of 37 slices covering a 111mm superior-inferior extent of the brain were acquired over a 402s period, using a gradient echo echo-planar imaging pulse sequence that incorporated a 3D prospective acquisition correction to minimize effects of the head motion. The imaging parameters were: 96 × 96 acquisition matrix, 2.5×2.5×3.0 mm voxels; for 17 subjects: 134 measurements, 3000/40 ms repetition/echo time, 90° flip angle, no acceleration, 2.5 mm slice thickness with 0.5 mm interslice gap; For 19 subjects: 174 measurements, 2250/30 ms repetition/echo time, 78° flip angle, GRAPPA acceleration factor of 2, 3.0 mm slice thickness with no inter-slice gap. These minor acquisition differences were necessary given an upgrade to the Trio. Whole-brain voxel-wise testing of the two acquisitions showed no significant differences in BOLD activation to olfactory stimulation using the appetitively neutral NApO (p < 0.05, false discovery rate corrected).
