Neuroimaging Protocol for Orbitofrontal Cortex and Amygdala

The study was conducted at the Wellcome Trust Centre for Neuroimaging at University College London using a 3T Siemens Allegra scanner. Functional scans used a gradient echo sequence optimised for orbitofrontal cortex and amygdala coverage (Weiskopf et al., 2007 (link)). Time of repetition (TR) = 2.52 s, time of echo (TE) = 30 ms, flip angle (FA) = 90°, matrix = 64 × 64, field of view (FOV) = 192 × 192 mm², slice thickness = 2 mm. Forty two axial slices (–30° tilt) were sampled for whole brain coverage, in-plane resolution = 3 × 3 mm. An MPRAGE sequence was used to acquire structural images after session 3 which comprised 1-mm-thick axial slices parallel to the anterior commissure/posterior commissure plane. Imaging data were analyzed with SPM5 (Wellcome Trust Centre for Neuroimaging). Images were realigned with the first volume (after discarding six dummy volumes) and unwarped, normalized to the the Montreal Neurological Institute reference template, resampled to 2 × 2 × 2 mm³ voxels, and spatially smoothed (8 mm full width at half-maximum).