Results of LPS are given in terms of IQ scores with a mean of 100 and a standard deviation of 15. The multiple choice vocabulary test (Mehrfachwahl Wortschatztest-Form B, MWT-B) is a German test to measure verbal intelligence and is thought to be a valid indicator of pre-morbid intelligence (Lehrl, 1989). Memory functions were tested by the Auditory-Verbal Learning Test (AVLT; Schmidt, 1996) and the Wechsler Memory Scale-Revised (WMS-R; Wechsler, 1987). The Trail Making Test (TMT; Reitan, 1992) was assessed Ku-0059436 manufacturer to measure visuospatial ability (TMT-A)

and executive function (TMT-B). The Wisconsin Card Sorting Test (WCST) was also conducted to test executive function (Heaton et al., 1993). MRI investigations were performed with a conventional head-cage coil on a 1.5-Tesla system (Vision Magnetom; Siemens, Erlangen, Germany) with gradients of 25 mT/m, SB203580 as described by us previously (Fellgiebel et al., 2004). DTI images were acquired with a transversal diffusion-weighted single-shot spin-echo echo-planar-based sequence in six non-collinear

diffusion-sensitizing gradient directions with diffusion sensitivity b = 900 mm2/s and one acquisition without diffusion encoding (b = 0 mm2/s). The acquisition matrix was 128 × 128, with 5 mm slice thickness. Repetition time (TR) was 8000 ms, echo time (TE) was 100 ms. All transversal slices were arranged parallel to the AC–PC line. At the time when the study was planned in 2003, these were standard imaging parameters. Original MR diffusion images were registered in DICOM format and converted to ANALYZE format using MRIcro software (University Miconazole of Nottingham, UK). All scans were inspected visually. None of the data sets in our sample had to be excluded. The T2-weighted images were normalized to the MNI (Montreal Neurological Institute) T2 template using SPM2 (statistical parametric mapping; Wellcome Department of Cognitive Neurology,

London, UK) software implemented in MatLab 6.5 (Mathworks, Sherborn, MA, USA). Identical normalization parameters were used for warping of the diffusion-weighted images such that each voxel represents the same part of the brain in every subject. For the calculation of FA and MD maps, the FDT tool (FMRIB’s Diffusion Toolbox) of the FSL software library (FMRIB’s software library) was used. The obtained FA and MD maps were then smoothed with a 9-mm isotropic FWHM Gaussian kernel to improve signal-to-noise ratio and normalization. Voxel-based FA and MD contrast analyses were then done to compare ADHD patient and control groups using General Linear Model (GLM) standard independent sample t-test.