Single nucleotide polymorphism in the neuroplastin locus associates with cortical thickness and intellectual ability in adolescents.

Despite the recognition that cortical thickness is heritable and correlates with intellectual ability in children and adolescents, the genes contributing to individual differences in these traits remain unknown. We conducted a large-scale association study in 1583 adolescents to identify genes affecting cortical thickness. Single-nucleotide polymorphisms (SNPs; n=54,837) within genes whose expression changed between stages of growth and differentiation of a human neural stem cell line were selected for association analyses with average cortical thickness. We identified a variant, rs7171755, associating with thinner cortex in the left hemisphere (P=1.12 × 10(-)(7)), particularly in the frontal and temporal lobes. Localized effects of this SNP on cortical thickness differently affected verbal and nonverbal intellectual abilities. The rs7171755 polymorphism acted in cis to affect expression in the human brain of the synaptic cell adhesion glycoprotein-encoding gene NPTN. We also found that cortical thickness and NPTN expression were on average higher in the right hemisphere, suggesting that asymmetric NPTN expression may render the left hemisphere more sensitive to the effects of NPTN mutations, accounting for the lateralized effect of rs7171755 found in our study. Altogether, our findings support a potential role for regional synaptic dysfunctions in forms of intellectual deficits.

Cortical thickness of superior frontal cortex predicts impulsiveness and perceptual reasoning in adolescence.

Impulsiveness is a pivotal personality trait representing a core domain in all major personality inventories. Recently, impulsiveness has been identified as an important modulator of cognitive processing, particularly in tasks that require the processing of large amounts of information. Although brain imaging studies have implicated the prefrontal cortex to be a common underlying representation of impulsiveness and related cognitive functioning, to date a fine-grain and detailed morphometric analysis has not been carried out. On the basis of ahigh-resolution magnetic resonance scans acquired in 1620 healthy adolescents (IMAGEN), the individual cortical thickness (CT) was estimated. Correlations between Cloninger's impulsiveness and CT were studied in an entire cortex analysis. The cluster identified was tested for associations with performance in perceptual reasoning tasks of the Wechsler Intelligence Scale for Children (WISC IV). We observed a significant inverse correlation between trait impulsiveness and CT of the left superior frontal cortex (SFC; Monte Carlo Simulation P<0.01). CT within this cluster correlated with perceptual reasoning scores (Bonferroni corrected) of the WISC IV. On the basis of a large sample of adolescents, we identified an extended area in the SFC as a correlate of impulsiveness, which appears to be in line with the trait character of this prominent personality facet. The association of SFC thickness with perceptual reasoning argues for a common neurobiological basis of personality and specific cognitive domains comprising attention, spatial reasoning and response selection. The results may facilitate the understanding of the role of impulsiveness in several psychiatric disorders associated with prefrontal dysfunctions and cognitive deficits.

DTNBP1 (dysbindin) gene variants: in vivo evidence for effects on hippocampal glutamate status.

INTRODUCTION: In linkage and association studies the DTNBP1 gene has been identified as a major susceptibility gene for schizophrenia. Reduced expression of DTNBP1 was found in the hippocampus and prefrontal cortex in post mortem brains of schizophrenic patients. In vitro and animal models provide evidence that the DTNBP1 gene product dysbindin modulates the activity of the neurotransmitter glutamate in hippocampal neurons and is crucial for cell functioning and synaptogenesis. This study is the first to investigate the effects of genetic variants of DTNBP1 on the status of the glutamate system as well as neuronal integrity (N-acetylaspartate, NAA) in the hippocampus and a cortical region, the anterior cingulate cortex (ACC), in humans. METHODS: In 79 healthy subjects, the association of single nucleotide polymorphisms (SNPs) rs760665 and rs909706 with absolute concentrations of glutamate and NAA in the left hippocampus and the ACC were investigated, using proton magnetic resonance spectroscopy (MRS) at 3 Tesla and a well established quantification procedure. RESULTS: Hippocampal glutamate concentration was significantly affected by genotype of rs760665 (F=4.406, df=2,p=0.016) and rs909706 (F=3.171,df=2,p=0.048). For the concentration of NAA, a weak association with rs760665 was observed in the contrast analysis. None of the metabolites measured in the ACC showed a significant connection with either genotype. CONCLUSION: The results support a role of DTNBP1 gene variants in the glutamate neurotransmission system in the human brain at least in the hippocampus. This is compatible to growing evidence of a crucial role of glutamate in the pathobiology of schizophrenia. In addition, the weak association between DTNBP1 genotype and NAA is in line with a regulatory influence of dysbindin on synaptogenesis and neuronal survival.

Matter wave diffraction from an inclined transmission grating: searching for the elusive 4He trimer Efimov state.

The size of the helium trimer is determined by diffracting a beam of 4He clusters from a 100 nm period grating inclined by 21 degrees. Because of the bar thickness the projected slit width is roughly halved to 27 nm, increasing the sensitivity to the trimer size. The peak intensities measured out to the eighth order are evaluated via a few-body scattering theory. The trimer pair distance is found to be (r) = 1.1(+0.4)(-0.5) nm in agreement with predictions for the ground state. No evidence for a significant amount of Efimov trimers is found. Their concentration is estimated to be under 6%, less than expected.

[Surgical accidents during repair of intracranial aneurysms]. / Incidents chirurgicaux au cours de la chirurgie des anévrysmes intra-craniens.

The need to discuss incidents encountered during cerebral aneurysm surgery--as well as techniques and results--is increasingly accepted. Single incidents, however, do not allow for general conclusions; we wish to present 5 cases, analysis of which, we believe, is likely to elucidate the trouble of diagnosis and intraoperative decision making.

[Histochemical and ultrastructural study of cytochrome-oxydase in basal cell epithelioma]. / Etude histochimique et ultrastructurale de la cytochrome-oxydase dans l'épithélioma baso-cellulaire

The activity of cytochrome-oxydase is less pronounced in the basal cell epithelioma than in the basal cells of the surrounding normal epidermis. The electron microscopic study of the localisation of the enzyme reveals that the cells of the basal cell epithelioma contain two types of mitochondria, the first of which having the same size as the epidermal mitochondria, and the other being giant mitochondria. The latter seem to be less active. The weak reactivity of the basal cell epithelioma for cytochrome-oxydase is probably due to the reduction of the cristae in mitochondria and to the functional deficiency of the giant mitochondria.

[Ultrastructure of solid basalioma. A morphometric study (author's transl.)]. / Zur Ultrastruktur des soliden Basalioms. Eine morphometrische Untersuchung

A morphometric investigation was made on mitochondria of basalioma cells and the cells of the basal layer of the epidermis lying over the tumor. The mitochondria of the basalioma cells occupy 4.7% and of the epidermal basal cells 5.3% of the cytoplasm. The number of mitochondrial sections yields a relation of 6.6:10 in favor of the epidermal cells. These results demonstrate an alteration in the size of the basalioma cell mitochondria. The possible causes of this mitochondria enlargement were discussed. An attenuation of the activities of the mitochondrial, membrane-bound enzymes in the basalioma cells is caused in all probability primarily by a reduction of the cristae material in comparison to the basal epidermal cells. The nucleus-cytoplasm relation amounts to 6.3:10 in the basalioma cells and 3.0:10 in the basal epidermal cells.