====== Time-averaged T2* ======

**Acquisition**
  * MRI data was acquired over 90 min on a 3 T Siemens Biograph mMR PET/MRI scanner.
    * T1 weighted magnetization-prepared rapid gradient-echo (MPRAGE) sequence 
      * (TR, 2300 ms; echo time (TE), 2.98 ms; flip angle, 9°; inversion time (T1), 900 ms; voxel size, 1.0 × 1.0 × 1.0 mm)
  * Functional images were acquired using blood oxygen level dependent (BOLD) signal from an echoplanar sequence 
    * (TR, 1500 ms; TE, 30 ms; flip angle, 50°; voxel size, 2.3 ×2.3 mm in-plane resolution) with contiguous 2.3 mm – thick slices aligned to maximally cover the cortex and basal ganglia.

** Processing **
  * Each volume was normalized to the whole-brain mean (z-score normalization
    * Coverage map created from all inputs for each participant
  * The normalized signal was aggregated voxel-wise across all volumes using the median 
  * Resulted in one normalized T2* -weighted (nT2*w) image for each participant (nT2*w)
  * High motion time points were identified as volumes containing frame-wise displacement (FD) > 0.3 mm were excluded 
  * nT2*w values were extracted separately across each basal ganglia region of interest (ROI) using the Harvard-Oxford subcortical atlas (Jenkinson et al., 2011)
    * Pallidum, nucleus accumbens (NAcc), putamen, and caudate nucleus

Inverse relation to [[brain:iron]], proxy for [[:brain:DA]]

   * ''tat2'' in [[tools:lncdtools|LNCD Tools]]
   * [[publications:parr_dopamineinhibitorycontrol|Contributions of dopamine-related basal ganglia neurophysiology to the developmental effects of incentives on inhibitory control]]