Using the same OBIC dataset, structural covariance analysis of four striatal regions and two amygdala regions was performed, showing increased covariance between the volume of the ventral‐rostral putamen and the left inferior frontal gyrus/operculum. Consistent with the previous findings, this association was only significant in older OCD patients, suggesting that these alterations may develop over the course of the disease (Subira et al., 2016). In addition to this fronto‐striatal finding, increased covariance was found between the right centromedial‐superficial part of the amygdala and the ventromedial prefrontal cortex, consistent with the role of the limbic circuit in OCD, as evident in functional MRI studies on emotional processing in this disorder (Milad et al., 2013; Thorsen et al., 2018).
