Brain activity during a visuospatial working memory task predicts arithmetical performance 2 years later

Visuospatial working memory (WM) capacity is highly correlated with mathematical reasoning abilities and can predict future development of arithmetical performance. Activity in the intraparietal sulcus (IPS) during visuospatial WM tasks correlates with interindividual differences in WM capacity. This region has also been implicated in numerical representation, and its structure and activity reflect arithmetical performance impairments (e.g., dyscalculia). We collected behavioral (N = 246) and neuroimaging data (N = 46) in a longitudinal sample to test whether IPS activity during a visuospatial WM task could provide more information than psychological testing alone and predict arithmetical performance 2 years later in healthy participants aged 6–16 years. Nonverbal reasoning and verbal and visuospatial WM measures were found to be independent predictors of arithmetical outcome. In addition, WM activation in the left IPS predicted arithmetical outcome independently of behavioral measures. A logistic model including both behavioral and imaging data showed improved sensitivity by correctly classifying more than twice as many children as poor arithmetical performers after 2 years than a model with behavioral measures only. These results demonstrate that neuroimaging data can provide useful information in addition to behavioral assessments and be used to improve the identification of individuals at risk of future low academic performance

The desmosomal cadherin desmoglein-3 acts as a keratinocyte anti-stress protein via suppression of p53

Desmoglein-3 (Dsg3), the Pemphigus Vulgaris (PV) antigen (PVA), plays an essential role in keratinocyte cell–cell adhesion and regulates various signaling pathways involved in the progression and metastasis of cancer where it is upregulated. We show here that expression of Dsg3 impacts on the expression and function of p53, a key transcription factor governing the responses to cellular stress. Dsg3 depletion increased p53 expression and activity, an effect enhanced by treating cells with UVB, mechanical stress and genotoxic drugs, whilst increased Dsg3 expression resulted in the opposite effects. Such a pathway in the negative regulation of p53 by Dsg3 was Dsg3 specific since neither E-cadherin nor desmoplakin knockdown caused similar effects. Analysis of Dsg3−/− mouse skin also indicated an increase of p53/p21WAF1/CIP1 and cleaved caspase-3 relative to Dsg3+/− controls. Finally, we evaluated whether this pathway was operational in the autoimmune disease PV in which Dsg3 serves as a major antigen involved in blistering pathogenesis. We uncovered increased p53 with diffuse cytoplasmic and/or nuclear staining in the oral mucosa of patients, including cells surrounding blisters and the pre-lesional regions. This finding was verified by in vitro studies where treatment of keratinocytes with PV sera, as well as a characterized pathogenic antibody specifically targeting Dsg3, evoked pronounced p53 expression and activity accompanied by disruption of cell–cell adhesion. Collectively, our findings suggThe study was supported by the Barts and The London School of Medicine and Dentistry and Guizhou Medical University, China. The animal work was supported by Deutsche Forschungsgemeinschaft (TR-SFB 156). Jutamas Uttagomol was supported by a scholarship from Naresuan University, Thailand

Use of an implantable loop recorder to increase the diagnostic yield in unexplained syncope: results from the PICTURE registry

To collect information on the use of the Reveal implantable loop recorder (ILR) in the patient care pathway and to investigate its effectiveness in the diagnosis of unexplained recurrent syncope in everyday clinical practice

Processing Ordinality and Quantity: The Case of Developmental Dyscalculia

In contrast to quantity processing, up to date, the nature of ordinality has received little attention from researchers despite the fact that both quantity and ordinality are embodied in numerical information. Here we ask if there are two separate core systems that lie at the foundations of numerical cognition: (1) the traditionally and well accepted numerical magnitude system but also (2) core system for representing ordinal information. We report two novel experiments of ordinal processing that explored the relation between ordinal and numerical information processing in typically developing adults and adults with developmental dyscalculia (DD). Participants made “ordered” or “non-ordered” judgments about 3 groups of dots (non-symbolic numerical stimuli; in Experiment 1) and 3 numbers (symbolic task: Experiment 2). In contrast to previous findings and arguments about quantity deficit in DD participants, when quantity and ordinality are dissociated (as in the current tasks), DD participants exhibited a normal ratio effect in the non-symbolic ordinal task. They did not show, however, the ordinality effect. Ordinality effect in DD appeared only when area and density were randomized, but only in the descending direction. In the symbolic task, the ordinality effect was modulated by ratio and direction in both groups. These findings suggest that there might be two separate cognitive representations of ordinal and quantity information and that linguistic knowledge may facilitate estimation of ordinal information

A numerical model of birch pollen emission and dispersion in the atmosphere. Description of the emission module

A birch pollen emission model is described and its main features are discussed. The development of the model is based on a double-threshold temperature sum model that describes the propagation of the flowering season and naturally links to the thermal time models to predict the onset and duration of flowering. For the flowering season, the emission model considers ambient humidity and precipitation rate, both of which suppress the pollen release, as well as wind speed and turbulence intensity, which promote it. These dependencies are qualitatively evaluated using the aerobiological observations. Reflecting the probabilistic character of the flowering of an individual tree in a population, the model introduces relaxation functions at the start and end of the season. The physical basis of the suggested birch pollen emission model is compared with another comprehensive emission module reported in literature. The emission model has been implemented in the SILAM dispersion modelling system, the results of which are evaluated in a companion paper

Developmental dyscalculia: a dysconnection syndrome?

Numerical understanding is important for everyday life. For children with developmental dyscalculia (DD), numbers and magnitudes present profound problems which are thought to be based upon neuronal impairments of key regions for numerical understanding. The aim of the present study was to investigate possible differences in white matter fibre integrity between children with DD and controls using diffusion tensor imaging. White matter integrity and behavioural measures were evaluated in 15 children with developmental dyscalculia aged around 10 years and 15 matched controls. The main finding, obtained by a whole brain group comparison, revealed reduced fractional anisotropy in the superior longitudinal fasciculus in children with developmental dyscalculia. In addition, a region of interest analysis exhibited prominent deficits in fibres of the superior longitudinal fasciculus adjacent to the intraparietal sulcus, which is thought to be the core region for number processing. To conclude, our results outline deficient fibre projection between parietal, temporal and frontal regions in children with developmental dyscalculia, and therefore raise the question of whether dyscalculia can be seen as a dysconnection syndrome. Since the superior longitudinal fasciculus is involved in the integration and control of distributed brain processes, the present results highlight the importance of considering broader domain-general mechanisms in the diagnosis and therapy of dyscalculia

Discalculia do desenvolvimento: avaliação da representação numérica pela ZAREKI-R

O presente estudo investigou aspectos da representação numérica (processamento numérico e cálculo) e memória operacional de crianças com transtornos de aprendizagem. Participaram 30 crianças de idade entre 9 e 10 anos, ambos os gêneros, divididas em dois grupos: sem dificuldade em aritmética (SDA; N=11) e com dificuldade em aritmética (CDA; N=19), avaliadas pela ZAREKI-R, Matrizes Coloridas de Raven, o Blocos de Corsi e o BCPR. Crianças CDA exibiram escores levemente mais baixos que as SDA quanto ao nível intelectual e nos Blocos de Corsi. Na ZAREKI-R apresentaram prejuízo nos subtestes ditado de números, cálculo mental, problemas aritméticos e total. Crianças CDA apresentaram déficits específicos em memória operacional visuoespacial e comprometimento em processamento numérico e cálculo, compatível com discalculia do desenvolvimento.This study investigated which aspects of number processing and calculation and working memory are related to arithmetic deficits. The participants were children aged from 9 to 10 years, both gender, divided in two groups based on their calculation score: a group without arithmetic disability (SDA; N=11) and with arithmetic disability (CDA; N=19); assessed by the instruments: ZAREKI-R, Raven's Coloured Progressive Matrices, Block Span, Digit Span, and CPR (pseudowords repetition). CDA children exhibited slightly lower scores than SDA on intellectual level and Block Span, and deficits in dictation of numbers, mental calculation, and problem solving tasks of the ZAREKI-R. The results indicate that CDA children have specific deficits in visuospatial working memory and performed poorly in number representation tasks, which fulfill criteria for Developmental Dyscalculia.Universidade Estadual Paulista Júlio de Mesquita FilhoUniversidade Estadual Paulista Júlio de Mesquita Filh

Dysfunctional neural network of spatial working memory contributes to developmental dyscalculia

The underlying neural mechanisms of developmental dyscalculia (DD) are still far from being clearly understood. Even the behavioral processes that generate or influence this heterogeneous disorder are a matter of controversy. To date, the few studies examining functional brain activation in children with DD mainly focus on number and counting related tasks, whereas studies on more general cognitive domains that are involved in arithmetical development, such as working memory are virtually absent. There are several studies showing a close relationship between DD and spatial working memory [Camos, V. (2008). Low working memory capacity impedes both efficiency and learning of number transcoding in children. Journal of Experimental Child Psychology, 99(1), 37-57; McLean, J. F., & Hitch, G. J. (1999). Working memory impairments in children with specific arithmetic learning difficulties. Journal of Experimental Child Psychology, 74(3), 240-260; Rosselli, M., Matute, E., Pinto, N., & Ardila, A. (2006). Memory abilities in children with subtypes of dyscalculia. Developmental Neuropsychology, 30(3), 801-818; Siegel, L. S., & Ryan, E. B. (1989). The development of working memory in normally achieving and subtypes of learning disabled children. Child Development, 60(4), 973-980]. The relationship between these two mechanisms is still matter of debate, but this study follows the assumption that poor spatial working memory capacity may hinder the acquisition of spatial number representations in children with DD [Geary, D. C. (1993). Mathematical disabilities: Cognitive, neuropsychological, and genetic components. Psychological Bulletin, 114(2), 345-362; von Aster, M., & Shalev, R. S. (2007). Number development and developmental dyscalculia. Developmental Medicine and Child Neurology, 49(11), 868-873]. Using functional MRI the current study compares brain activity associated with spatial working memory processes in 8-10-year-old children with DD and normally achieving controls. Both groups showed significant spatial working memory related activity in a network including occipital and parietal regions. Children with DD showed weaker neural activation compared to the control group during a spatial working memory task in the right intraparietal sulcus (IPS), the right insula and the right inferior frontal lobe. Performance tests outside the scanner showed impaired working memory proficiency in children with DD. Bringing behavioral performance and neural activity together we found significant correlations of right IPS activity with performance on the verbal digit span forward and the spatial Corsi Block Tapping test. Our findings demonstrate for the first time an involvement of spatial working memory processes in the neural underpinnings of DD. These poor spatial working memory processes may inhibit the formation of spatial number representations (mental numberline) as well as the storage and retrieval of arithmetical facts

Climate effects on productivity and resource-use efficiency of Norway spruce (Picea abies [L.] Karst.) and European beech (Fagus sylvatica [L.]) in stands with different spatial mixing patterns

ArticleSpecies mixing is widely held to stabilize productivity, increase resilience and contribute to risk minimization in forest stands in need of special as a result of longevity. However, research on the effects of mixing on productivity and resource consumption so far yielded fairly incoherent results rather than general findings. We focused on the effects of the spatial mixing pattern and the annual climate conditions on the mixing effect, which to date have seldom been considered as modifiers of mixing effects. Nine years of intensive survey of four pure stands of Norway spruce (Picea abies [L.] Karst.) and European beech (Fagus sylvatica [L.]) and two mixed plots with different mixing pattern showed: (1) mixing hardly changed annual net primary productivity at stand level when Norway spruce and European beech are cultivated group-wise but increased by 37 % on account of a higher efficiency of water and light use in individual tree-wise mixture. (2) Favourable climatic conditions increased the superiority of mixed versus pure stands productivity, while, in particular, water stress cancelled the benefit of mixing considerably. (3) An interaction between the spatial pattern and variable climatic conditions was revealed. Both improved light and water use were found in favourable years in close inter-specific intermingling. However, in unfavourable years the spatial pattern played a less pronounced role in terms of productivity. © 2012 Springer-Verlag

Optimized voxel-based morphometry in children with developmental dyscalculia.

Developmental dyscalculia (DD) is a specific learning disability affecting the normal acquisition of arithmetic skills. Current studies estimate that 3-6% of the school population is affected by DD. Genetic, neurobiological, and epidemiologic evidence indicates that dyscalculia is a brain-based disorder. Imaging studies suggest the involvement of parietal and prefrontal cortices in arithmetic tasks. The aim of the present study was to analyze if children with DD show structural differences in parietal, frontal, and cingulate areas compared to typically achieving children. Magnetic resonance imaging was obtained from 12 children with DD aged 9.3+/-0.2 years and 12 age-matched control children without any learning disabilities on a 1.5 T whole-body scanner. Voxel-based morphometry analysis with an optimization of spatial segmentation and normalization procedures was applied to compare the two groups in order to find differences in cerebral gray and white matter. Compared to controls, children with DD show significantly reduced gray matter volume in the right intraparietal sulcus (IPS), the anterior cingulum, the left inferior frontal gyrus, and the bilateral middle frontal gyri. White matter comparison demonstrates clusters with significantly less volume in the left frontal lobe and in the right parahippocampal gyrus in dyscalculic children. The decreased gray and white matter volumes in the frontoparietal network might be the neurological substrate of impaired arithmetic processing skills. The white matter volume decrease in parahippocampal areas may have influence on fact retrieval and spatial memory processing