Resting gamma power during the postnatal critical period for GABAergic system development is modulated by infant diet and sex.

Gamma band activity (30-50 Hz) plays an essential role in brain development and function, but neither the early postnatal development nor subject and environmental factors influencing this development have been reported. We documented the development of resting gamma power using high density EEG recordings obtained each month from postnatal month 2 to 6 in 518 healthy infants who were breast-fed (170; 85 boys), fed milk formula (186; 97 boys), or fed soy formula (162; 90 boys). Gamma power was determined for 44 sites distributed over major brain regions and analyses were adjusted for background variables relevant to neurodevelopment. The results show gamma power follows a gradually increasing function across this time period that varies in topographic magnitude and is differentially influenced by subject and environmental variables-among which gestation, head circumference, and infant diet-sex interactions figure most prominently. Relationships between gamma power and standardized measures of infant behavioral development appear to be emerging but are in flux during this time. Since this postnatal period is considered critical in the development of the GABAergic system underlying the generation of gamma activity, the observed findings may reflect organizational changes that will influence the future development of gamma-related behavioral and neurocognitive functions.

White Matter Microstructure Correlates with Memory Performance in Healthy Children: A Diffusion Tensor Imaging Study.

BACKGROUND AND PURPOSE: The complex function of memory has been linked to both brain gray and white matter (WM). WM abnormalities are associated with memory impairment in pathological conditions. We investigated whether variation in WM microstructure in healthy children also correlates with memory performance. METHODS: Sixty-five 7.5 to 8.5-year-old healthy children had a brain MRI scan using diffusion tensor imaging (DTI). They were also assessed for memory performance using the Children's Memory Scale (CMS). Eight indices that evaluate verbal and visual memory (immediate and delayed) were measured. DTI parameters reflecting WM microstructure, including fractional anisotropy (FA), mean diffusivity (MD), radial diffusivity (RD), and axial diffusivity (AD), were calculated and correlated with memory indices. RESULTS: Tract-based spatial statistics analysis showed multiple WM tracts in which DTI parameters correlated with CMS indices. Specifically, FA (a reflection of WM integrity) and RD values (a reflection of myelination) in multiple projecting, association, and commissural WM tracts correlated with verbal delayed index (P < .05, corrected for voxel-wise multiple comparisons). Also, FA values in several WM tracts, including superior longitudinal fasciculus and posterior corona radiata, positively correlated with delayed recognition index (P < .05, corrected). Region of interest analyses showed similar correlations between FA/RD and CMS scores in WM regions involving these tracts and additionally in the cingulum, and detected additional MD-CMS correlations in several regions. CONCLUSIONS: Significant correlations between DTI parameter values and CMS indices in multiple WM tracts in healthy children indicate that neuroimaging can sensitively detect brain WM changes associated with variations of memory function, even for that in the normal range.

Differences in academic and executive function domains among children with ADHD Predominantly Inattentive and Combined Types.

Differences between the subtypes of Attention Deficit Hyperactivity Disorder (ADHD) continue to have a place in the clinical and research literature. The purpose of this study was to examine differences specific to academic and executive function deficits in a sample of 40 children, aged 9-15 years. Although there was a tendency for the Predominantly Inattentive (PI) group to evidence lower performance on calculation and written expression tasks, these differences dissipated when IQ was included as a covariate. For executive function domains of set shifting, interference, inhibition, and planning, differences emerged for interference, but only when girls were excluded from the analysis and no control for IQ was made. For parent ratings of executive function, expected differences were found on the Inhibit scale with the Combined Type (CT) group evidencing greater problems in this area; this difference remained even when girls were excluded and IQ was controlled. Implications for research and practice are presented.

Digit Span components as predictors of attention problems and executive functioning in children.

This study examined the extent to which digits forward (DF) or digits backward (DB) account for variance in parent ratings of attention and executive function in children. The sample (n=90) included children with no diagnosis and children with a range of clinical problems, including attention deficit hyperactivity disorder (ADHD). Clinical groups differed from the No Diagnosis group on cognitive ability as well as achievement. Once cognitive ability was controlled, no group differences emerged for Digit Span or digits forward; notably, the ADHD-Predominantly Inattentive group was able to recall significantly more digits backward than the ADHD-Combined Type group. Regression analyses indicated that Full Scale IQ explained significant variance in parent ratings of attention and executive function; DF emerged as a significant predictor only for one measure of attention. When only children with ADHD were considered, DF no longer was a significant predictor. Results support the notion that DF and DB are differing constructs, as well as highlighting the importance of controlling for cognitive ability in consideration of group differences on behavioral measures.

Assessment of attention deficit hyperactivity disorder (ADHD) using the BASC and BRIEF.

There has been an overwhelming increase in the number of children diagnosed with attention deficit hyperactivity disorder (ADHD). School and clinical psychologists play an important role in the assessment of a child's emotional and behavioral difficulties, including problems with attention. Various assessment measures, including behavioral rating forms such as the Behavior Assessment System for Children (BASC) and the Behavior Rating Inventory of Executive Function (BRIEF), are often used in the assessment of a child's behavior. The purpose of this article is to provide more knowledge to psychologists regarding the assessment of ADHD in children using the BASC and BRIEF. Results from this study indicated that the BASC and BRIEF scales appear to be measuring similar, but different, constructs pertaining to behaviors associated with ADHD, as well as similar study skills and learning problems. These findings suggest that children diagnosed with ADHD are rated lower on adaptive skills when compared to children with no diagnosis on the BASC. Use of the BASC and BRIEF in ADHD assessment appears promising and may generate additional areas in need of intervention.