Functional MRI acquisition protocol

A 3-T whole-body Siemens scanner (TrioTim Syngo; Siemens, Erlangen, Germany) with a 12-channel birdcage head coil was used for functional image acquisition with an interleaved T2*-weighted echo-planar imaging gradient echo sequence (repetition time = 3000 ms for picture stimulus, 2000 ms for sound and Stroop stimuli; echo time/flip angle = 30 ms/90°; slice thickness = 3.0 mm; in-plane resolution = 3.4 × 3.4 mm; field of view = 220 mm; matrix size = 64 × 64). The experiment was conducted in an fMRI room using an 8-in. screen; stimuli were presented by means of DMDX software. For each participant, the following numbers of functional volumes were acquired: 174 for picture runs, 185 for Stroop runs, and 159 for sound runs. After fMRI, an anatomical image was acquired using a high, T1-weighted, 3D gradient echo pulse sequenced with magnetization-prepared rapid gradient echo (repetition time/echo time/inversion time/flip angle = 1670 ms/1.89 ms/900 m/9°, slice thickness = 1.0 mm, in-plane resolution = 1 × 1 mm, field of view = 250 mm, matrix size = 256 × 256). The total duration of the experiment was approximately 40 min. Before MRI was performed, previous hypnotics or psychotropic medication were washed out for at least four half-lives of the drugs. The method of MRI data acquisition process is cited from Kim et al. study^{21 (link)}.