Another direction of research that is currently in preparation is the meta‐analysis of resting‐state functional MRI. Resting‐state fMRI (rs‐fMRI) can provide multiple measures of functional connectivity that are thought to index the communication between distinct brain regions. A recent meta‐analysis based on reported findings in the literature found that multiple resting‐state networks are affected in OCD (Gursel et al., 2018). Moreover, a single‐site study suggests that rs‐fMRI can predict the outcome of CBT (Reggente et al., 2018). To obtain robust estimations of functional connectivity abnormalities in OCD, the consortium aims to perform functional connectivity analyses using the fmriprep + pipeline that has been developed by Veer and colleagues (Charité, Berlin). This pipeline uses the fMRI preprocessing stages from fmriprep (Esteban et al., 2019), and outputs various rs‐fMRI measures such as resting‐state networks based on independent components analysis and (partial) correlation matrices between distinct brain regions. Initially, the consortium will analyze average group differences in these measures between OCD patients and controls, and subsequently use machine‐learning methods to determine whether rs‐fMRI can provide a biomarker for OCD. Furthermore, the same methods
