Several studies of OUD have assessed functional connectivity within the DMN, with inconsistent findings. While several studies found decreased functional connectivity within the DMN, some studies found increased functional connectivity [7–11]. Fewer studies have assessed functional connectivity within the SN and ECN [3,12]. Both Upadhyay et al. (2010) and Wang et al. (2016) found decreased functional connectivity within the SN in OUD subjects relative to healthy controls. Li et al. (2018) found increased functional connectivity between the left ECN and the right ECN in OUD, but to our knowledge there are no published studies which have addressed functional connectivity within the left ECN or right ECN in OUD [13]. Furthermore, many of the above-referenced studies used seed-based functional connectivity methods which may be more prone to head motion confounds than independent component analysis (ICA) [1]. ICA allows for quantitative investigation of whole networks without the need for selection of a seed region of interest and can better account for artifacts compared to seed-based methods which can be influenced by spatial confounds [1]. ICA with subsequent analysis using the dual regression
