MRI acquisition

All MR scanning was performed on a 3T Siemens Trio scanner with 12-channel head coil at the University of Pittsburgh Magnetic Resonance Research Center. Whole-brain functional MR (fMRI) data were acquired axially using gradient-echo echo-planar imaging (EPI) sequence with the following parameters: repetition time (TR) = 2 s, echo time (TE) = 32 ms, flip angle = 90°, FOV = 256 × 256 mm ², acquisition matrix 128 × 128, slice thickness/gap = 4/0 mm (voxel size = 2 × 2 × 4 mm³), 28 axial slices. T1-weighted structural images were acquired in the axial plane using a magnetization-prepared rapid gradient echo sequence (T1w MPRAGE) with the following parameters: TR = 2 ms, TE = 3.4 ms, flip angle = 9°, FOV = 240 × 256 mm², matrix 240 × 256, slice thickness/gap = 1/0 mm (voxel size = 1 × 1 × 1 mm³), 160 slices and generalized autocalibrating partially parallel acquisitions (GRAPPA) acceleration factor = 2. T1w MPRAGE images were used to facilitate and improve the normalization of fMRI data into the Montreal Neurological Institute (MNI) template space. Resting state fMRI data (5 mins) were collected and participants were instructed to fixate on a central crosshair and to stay awake during image acquisition. Task fMRI data were collected while participants were performing a face-name memory associative memory task. The face-name memory encoding task is a mixed block/event-related design task. Each run of the task lasted 4 mins 36 secs, consisting of 2 experimental blocks and 2 control blocks, interspersed with 25-sec fixation. Each block lasted 48 secs, containing 8 sequential trails of face-name pairs, 5 secs each trial with 1 sec inter-trial interval. During the experimental blocks, participants were presented novel face-name pairs and were asked to subjectively decide and respond with an MR-compatible glove whether or not each name was a good fit for the face. This subjective decision was designed to strengthen the associative encoding of the face-name pairs (Sperling, Chua, et al., 2003). For the control blocks, two familiar face-name pairs, one female face-name pair and one male face-name pair, were repeatedly presented to the participants. The participants were trained and thus familiar with these two face-name pairs in the pre-scan session. Of the 61 participants, 44 participants completed three runs of the face-name task, 11 completed two runs, and 4 completed one run.