2008), which includes 50 WM tract labels created by hand segmentation of a standard-space average of diffusion MRI tensor maps from 81 subjects. Statistical threshold was set at P < 0.001, which is a relatively lenient threshold and a good trade-off between the control of false positive and reliability (Thirion et al. 2007). Results Sociodemographic and neuropsychological variables As expected from the matching

procedure, the two groups Inhibitors,research,lifescience,medical did not significantly differ for age, educational attainment and gender (see Table 1). Exploratory individual analyses revealed that the two diagnostic groups significantly differed relative to the Rey’s 15 word Immediate and Delayed Recall score, the TMT-B Inhibitors,research,lifescience,medical score and the SFT score. Specifically, OCD patients scored lower than HC in the Rey’s 15 word Immediate and Delayed Recall and the SFT, while needed significantly more time than controls to complete the TMT-B task (see Table 2). Table 2 Neuropsychological performance of 20 patients with OCD and 20 HC subjects However, the collinearity

among test variables Inhibitors,research,lifescience,medical was high in both groups as, for example, less than 30% of the variance associated with the Rey’s 15 word Immediate Recall score in the HC group was independent of other predictors (see Table 3). Inhibitors,research,lifescience,medical The latter variable was therefore excluded from the subsequent multivariate logistic regression, as the inclusion of both the Rey’s 15 word Immediate and Delayed Recall score would not have added more information to the model than the inclusion of just one of them. Table 3 Tolerance value for the neuropsychological variables where a significant difference between OCD and HC was observed The overall model including the Rey’s 15 word Delayed Recall score, the Inhibitors,research,lifescience,medical TMT-B score and the SFT score as predictor variables and the diagnostic group as dependent variable was significant (likelihood ratio: χ2 = 27.76; df = 3; P < 0.001) and explained 50% of the total variance (adjusted

R2). Specifically, 17-DMAG (Alvespimycin) HCl the SFT score was the only significant predictor of diagnosis (Odds Ratio [OR] = 1.37; 95% Confidence SRT1720 ic50 Intervals (CI) = 1.09–1.73; P = 0.0058] so that the odds of belonging to the OCD group increased about 1.4 times for each word omitted in the SFT. The overall prediction accuracy of the model was 87.50%, while 90% of OCD patients could be accurately classified on the basis of the SFT score. Neuroimaging Cortical/deep structures GM analysis and neuropsychological correlates Results of macrostructural-VBM analysis revealed no GM volumetric differences between OCD patients and HC subjects. Therefore, no correlation between GM volumetric measures and cognitive performance was examined.