Hemispheric Asymmetries in Cortical Thickness

Using magnetic resonance imaging and computational cortical pattern matching methods, we analyzed hemispheric differences in regional gray matter thickness across the lateral and medial cortices in young, healthy adults (n = 60). In addition, we investigated the influence of gender on the degree of thickness asymmetry. Results revealed global and regionally specific differences between the two hemispheres, with generally thicker cortex in the left hemisphere. Regions with significant leftward asymmetry were identified in the precentral gyrus, middle frontal, anterior temporal and superior parietal lobes, while rightward asymmetry was prominent in the inferior posterior temporal lobe and inferior frontal lobe. On the medial surface, significant rightward asymmetries were observed in posterior regions, while significant leftward asymmetries were evident from the vicinity of the paracentral gyrus extending anteriorly. Asymmetry profiles were similar in both sexes, but hemispheric differences appeared slightly pronounced in males compared with females, albeit a few regions also indicated greater asymmetry in females compared with males. Hemispheric differences in the thickness of the cortex might be related to hemisphere-specific functional specializations that are possibly related to behavioral asymmetrie

Relationships Between Sulcal Asymmetries and Corpus Callosum Size: Gender and Handedness Effects

Magnetic resonance imaging was used to establish the presence and nature of relationships between sulcal asymmetries and mid-sagittal callosal size in neurologically intact subjects, and to determine the influences of sex and handedness. Against a background of long-standing disputes, effects of gender and handedness on callosal size, shape, and variability were additionally examined. Both positive and negative correlations between sulcal asymmetry and callosal size were observed, with effects influenced by sex and handedness. The direction of relationships, however, were dependent on the regional asymmetry measured and on whether real or absolute values were used to quantify sulcal asymmetries. Callosal measurements showed no significant effects of sex or handedness, although subtle differences in callosal shape were observed in anterior and posterior regions between males and females and surface variability was increased in males. Individual variations in callosal size appear to outrange any detectable divergences in size between groups. Relationships between sulcal asymmetries and callosal size, however, are influenced by both sex and handedness. Whether magnitudes of asymmetry are related to increases or decreases in callosal size appears dependent on the chosen indicators of asymmetry. It is an oversimplification, therefore, to assume a single relationship exists between cerebral asymmetries and callosal connection

Specific refolding pathway of viscumin A chain in membrane-like medium reveals a possible mechanism of toxin entry into cell

How is a water-soluble globular protein able to spontaneously cross a cellular membrane? It is commonly accepted that it undergoes significant structural rearrangements on the lipid-water interface, thus acquiring membrane binding and penetration ability. In this study molecular dynamics (MD) simulations have been used to explore large-scale conformational changes of the globular viscumin A chain in a complex environment - comprising urea and chloroform/methanol (CHCl /MeOH) mixture. Being well-packed in aqueous solution, viscumin A undergoes global structural rearrangements in both organic media. In urea, the protein is "swelling" and gradually loses its long-distance contacts, thus resembling the "molten globule" state. In CHCl /MeOH, viscumin A is in effect turned "inside out". This is accompanied with strengthening of the secondary structure and surface exposure of hydrophobic epitopes originally buried inside the globule. Resulting solvent-adapted models were further subjected to Monte Carlo simulations with an implicit hydrophobic slab membrane. In contrast to only a few point surface contacts in water and two short regions with weak protein-lipid interactions in urea, MD-derived structures in CHCl /MeOH reveal multiple determinants of membrane interaction. Consequently it is now possible to propose a specific pathway for the structural adaptation of viscumin A with respect to the cell membrane - a probable first step of its translocation into cytoplasmic targets

Stochastic tomography, regional volumetric comparisons, and genotype-anatomical correlation in patients with spinocerebella ataxia type 6 and episodic ataxia type 2

International audienceno abstrac

Framework for Participants\u27 Recognition of Key Success Factors in Electronic Marketplaces

The development of electronic marketplaces ahs been prolific in the last five years and the pressure for companies to participate, before they have determined how to recognise the benefits and pitfalls, has been intense. This has left prospective participants facing a wide variety of choices in the selection of potential trading sites, in a marketplace that is both dynamic and immature. Although there are different drivers pushing companies towards participation, an appreciation of how electronic marketplaces are developing their trading models can support the selection process and enhance the trading experience of the participants