“…OCD is clinically characterized by the presence of intrusive thoughts and ritualistic behaviors which have been related to functional disturbances in different brain systems, including the frontostriatal circuits [Chamberlain et al, 2008;Evans et al, 2004;Harrison et al, 2009;Marsh et al, 2009;Menzies et al, 2008a;Stein, 2000]. In OCD, however, there is also evidence for anatomical alterations affecting white matter integrity, gray matter concentration, and gray matter volume in the frontal lobes, basal ganglia, and connected brain systems Kim et al, 2001;Menzies et al, 2008a,b;Pujol et al, 2004;Radua and Mataix-Cols, 2009;Rotge et al, 2009;Soriano-Mas et al, 2007;Szeszko et al, 2005 ].…”