0 years, age range = 8.2–15.6 years). Controls were originally recruited through community and hospital postings or were biological children of a participating adoptive or foster parent. None had a documented history of prenatal exposure to alcohol or other teratogenic substances, a learning disability, or other neurological or psychiatric condition. Demographics Inhibitors,research,lifescience,medical Parents or caregivers completed a child history form that included comprehensive information of the child’s prenatal, birth, developmental, and familial history. Socioeconomic
status (SES) was computed using the Hollingshead Four-Factor Index (Hollingshead 1975) based on the education and occupation of biological or foster parents. All participants were assessed for intelligence with the Wechsler Abbreviated Scale of Intelligence (WASI; Inhibitors,research,lifescience,medical Wechsler 1999), which provides a full-scale IQ score. Image acquisition and processing High-resolution T1-weighted MRI scans were obtained in the axial plane (repetition time = 10.06 msec, echo time = 4.2 msec, inversion time = 400 msec, flip angle = 20°, field of view = 180 mm, acquisition matrix = 256 × 192,
slice thickness = 1.5 mm) Inhibitors,research,lifescience,medical using a 1.5 Tesla GE signal excite scanner (selleck chemicals General Electric Medical Systems, Milwaukee, WI). All scans were processed using the automated CIVET pipeline (version 1.1.10; Montreal Neurological Institute at McGill University, Montreal, Quebec, Canada). First, they were registered to the symmetric ICBM 152 template (Collins et al. 1994) and then corrected for radiofrequency inhomogeneity (Sled et al. 1998). Next,
skulls were stripped from the brain tissue (Smith Inhibitors,research,lifescience,medical 2002), which was then classified into grey matter, white matter, and cerebrospinal fluid (CSF) Inhibitors,research,lifescience,medical components (Zijdenbos et al. 2002; Tohka et al. 2004). Deformable models were used to construct the inner white matter surface and grey matter–CSF interface or pial surface in both hemispheres (Kim et al. 2005). These yielded four surfaces of 40,962 vertex points per surface. CT was measured from each vertex point on the white matter surface to the corresponding pial-surface point (Lerch and Evans 2005). CT data were blurred with a 20-mm surface-based diffusion-blurring kernel (Chung and Taylor 2004) and nonlinearly aligned using surface-based registration (Lyttelton et al. 2007). SA however was computed at each vertex point of the pial surface by estimating the two dimensional area of a triangle formed by three vertices on the surface mesh and attributing a third of this area to each of the three vertices (Lyttelton et al. 2009). In addition to the vertex-wise analysis, each cortical hemisphere was segmented into sub-regions using the ANIMAL algorithm (Collins et al. 1995). From these data, measures of total cortical grey matter volume, total SA, and average CT were derived for each of the four hemispheric lobes (frontal, parietal, temporal, occipital), thus eight in total.