2.5 fMRI data acquisition and processing
All images were acquired through a 3.0-T Phillips Achieva DS scanner (Philips Medical Systems, Best, the Netherlands) with a 32-channel head coil. First, a T1-3D anatomical scan (TR/TE 8.2/3.8; matrix 240x240; 1x1x1 mm3 voxel; transverse slices) was taken. During the cue-reactivity task, echo planar images (EPIs) covering the whole brain were taken with a total of 36 ascending axial slices (3x3x3 mm3 voxel size; slice gap 3mm; TR/TE 1.999/28ms; matrix 80x80).
The MRI data was preprocessed using the fMRI prep 1.3.2 pipeline(Estebanet al. , 2019). First, the anatomical data was corrected for intensity nonuniformity, skull-stripped, spatially normalized, and segmented into cerebrospinal fluid, white matter, and gray matter. Second, the functional data was corrected for susceptibility distortions by using a deformation field followed by co-registration, motion-correction, and smoothing. Third, an independent component analysis for Automatic Removal of Motion Artifacts (ICA-AROMA)(Pruimet al. , 2015) was performed that automatically removed (head) motion artifacts and the data was resampled to standard space.
The current study utilized SPM12 to further analyze the fMRI data (http://www.fil.ion.ucl.ac.uk/spm). First level models included separate regressors for the cocaine clue block, the emotionally negative block, and the two neutral blocks. These regressors were convolved with a canonical hemodynamic response function. A high pass filter (1/128 Hz) was included in the first-level model to correct for low-frequency signal drift. The contrasts for the neutral, emotionally negative and cocaine blocks were subsequently entered in a second level model. Subsequently, the Marsbar toolbox (http://marsbar.sourceforge.net) was used to extract the mean activity for the contrasts for each region of interest (DS, VS, amygdala and dACC). In line with previous research , the VS was defined as the nucleus accumbens from the Harvard-Oxford subcortical structure probability atlas (http://www.cma.mgh.harvard.edu/fsl_atlas.html) and the DS was defined as the caudate and putamen from the automated anatomical labeling (AAL) atlas(Tzourio-Mazoyer et al. , 2002) minus the VS. The dACC was defined as the higher (z-coordinate> 78) part of the ACC defined by the AAL atlas. Finally, the amygdala mask was derived from the AAL atlas.