Gyrification in relation to cortical thickness in the congenitally blind

Greater cortical gyrification (GY) is linked with enhanced cognitive abilities and is also negatively related to cortical thickness (CT). Individuals who are congenitally blind (CB) exhibits remarkable functional brain plasticity which enables them to perform certain non-visual and cognitive tasks with supranormal abilities. For instance, extensive training using touch and audition enables CB people to develop impressive skills and there is evidence linking these skills to cross-modal activations of primary visual areas. There is a cascade of anatomical, morphometric and functional-connectivity changes in non-visual structures, volumetric reductions in several components of the visual system, and CT is also increased in CB. No study to date has explored GY changes in this population, and no study has explored how variations in CT are related to GY changes in CB. T1-weighted 3D structural magnetic resonance imaging scans were acquired to examine the effects of congenital visual deprivation in cortical structures in a healthy sample of 11 CB individuals (6 male) and 16 age-matched sighted controls (SC) (10 male). In this report, we show for the first time an increase in GY in several brain areas of CB individuals compared to SC, and a negative relationship between GY and CT in the CB brain in several different cortical areas. We discuss the implications of our findings and the contributions of developmental factors and synaptogenesis to the relationship between CT and GY in CB individuals compared to SC. F

Модификация полилактида бифункциональными соединениями

Объектом исследования является полилактид. Цель работы – подобрать оптимальные условия процесса модификации и модификаторы, приводящие к наибольшему увеличению молекулярной массы исходного низкомолекулярного полимера с сохранением необходимых свойств полимера. В процессе выполнения диссертации были подобраны оптимальные условия модификации, выбраны наилучшие модификаторы и методы контроля за протеканием процесса. Так же были рассмотрены вопросы безопасности и экономической эффективности данного процесса.Purpose - find the optimal conditions of the modification process and modifiers that lead to the greatest increase in the molecular weight of the starting low molecular weight polymer with maintaining the necessary properties of the polymer. In carrying out the Master's thesis were selected optimal conditions modification, the best modifier and the progress of the process control methods have been selected. Also, safety and economic efficiency of the process were discussed

The 1st INTEGRAL SPI-ACS Gamma-Ray Burst Catalogue

We present the sample of gamma-ray bursts detected with the anti-coincidence shield ACS of the spectrometer SPI on-board INTEGRAL for the first 26.5 months of mission operation (up to Jan 2005). SPI-ACS works as a nearly omnidirectional gamma-ray burst detector above ~80 keV but lacks spatial and spectral information. In this catalogue, the properties derived from the 50 ms light curves (e.g., T90, Cmax, Cint, variability, V/Vmax) are given for each candidate burst in the sample. A strong excess of very short events with durations <0.25 s is found. This population is shown to be significantly different from the short- and long-duration burst sample by means of the intensity distribution and V/Vmax test and is certainly connected with cosmic ray hits in the detector. A rate of 0.3 true gamma-ray bursts per day is observed.Comment: 10 pages, 9 figures, A&A accepte

The evolution of representation in simple cognitive networks

Representations are internal models of the environment that can provide guidance to a behaving agent, even in the absence of sensory information. It is not clear how representations are developed and whether or not they are necessary or even essential for intelligent behavior. We argue here that the ability to represent relevant features of the environment is the expected consequence of an adaptive process, give a formal definition of representation based on information theory, and quantify it with a measure R. To measure how R changes over time, we evolve two types of networks---an artificial neural network and a network of hidden Markov gates---to solve a categorization task using a genetic algorithm. We find that the capacity to represent increases during evolutionary adaptation, and that agents form representations of their environment during their lifetime. This ability allows the agents to act on sensorial inputs in the context of their acquired representations and enables complex and context-dependent behavior. We examine which concepts (features of the environment) our networks are representing, how the representations are logically encoded in the networks, and how they form as an agent behaves to solve a task. We conclude that R should be able to quantify the representations within any cognitive system, and should be predictive of an agent's long-term adaptive success.Comment: 36 pages, 10 figures, one Tabl

Intra-uterine exposure to selective serotonin reuptake inhibitors (SSRIs), maternal psychopathology, and neurodevelopment at age 2.5years-Results from the prospective cohort SMOK study

Background: Selective serotonin reuptake inhibitors (SSRIs) are prescribed in 2-8% during pregnancy. Whether prenatal exposure to SSRIs has long-term effects on the children's development is unknown. Aim: The aim of this study was to determine the effect of prenatal exposure to SSRIs on children's cognitive, motor, and behavioral outcomes at 2.5 years, adjusted for maternal depression and anxiety. Methods: In a prospective, longitudinal cohort-study we included 111 pregnant women treated either or not with an SSRI. We examined cognitive and motor development of their children at 2.5 years, using the Bayley Scale of Infant and Toddler Development, 3rd Edition, and measured emotional and behavioral problems using the parent-rated Child Behavior Checklist (CBCL). Maternal depression and anxiety was determined during pregnancy and at the children's assessment. Differences of normed cognitive, motor, and behavioral scores between SSRI-exposed and non-SSRI-exposed children were tested using multiple linear regression analyses. Results: We examined 102 children. SSRI-exposed children had lower scaled scores on cognition and gross motor development than non-SSRI-exposed children: 9.0 +/- 1.4 (mean +/- SD) versus 9.9 +/- 1.7 [P = 0.004], and 7.9 +/- 2.2 versus 9.0 +/- 2.5 [P = 0.01], respectively. Differences remained significant after adjusting for maternal depression and anxiety and other confounders in various models (mean difference for cognition 0.8 to 0.9 points, for gross motor 1.1 to 1.2 points). Only after adjusting for severity of maternal anxiety, differences in gross motor scores lost significance. Conclusions: Prenatal exposure to SSRIs is associated with poorer cognitive and gross motor development of the children at 2.5 years. Effects on gross motor development disappeared after correction for severity of maternal anxiety