COMT Val158Met polymorphism, cognitive stability and cognitive flexibility: an experimental examination

<p>Abstract</p> <p>Background</p> <p>Dopamine in prefrontal cortex (PFC) modulates core cognitive processes, notably working memory and executive control. Dopamine regulating genes and polymorphisms affecting PFC - including Catechol-O-Methyltransferase (COMT) Val158Met - are crucial to understanding the molecular genetics of cognitive function and dysfunction. A mechanistic account of the COMT Val158Met effect associates the Met allele with increased tonic dopamine transmission underlying maintenance of relevant information, and the Val allele with increased phasic dopamine transmission underlying the flexibility of updating new information. Thus, consistent with some earlier work, we predicted that Val carriers would display poorer performance when the maintenance component was taxed, while Met carriers would be less efficient when rapid updating was required.</p> <p>Methods</p> <p>Using a Stroop task that manipulated level of required cognitive stability and flexibility, we examined reaction time performance of patients with schizophrenia (n = 67) and healthy controls (n = 186) genotyped for the Val/Met variation.</p> <p>Results</p> <p>In both groups we found a Met advantage for tasks requiring cognitive stability, but no COMT effect when a moderate level of cognitive flexibility was required, or when a conflict cost measure was calculated.</p> <p>Conclusions</p> <p>Our results do not support a simple stability/flexibility model of dopamine COMT Val/Met effects and suggest a somewhat different conceptualization and experimental operationalization of these cognitive components.</p

La renovación de la palabra en el bicentenario de la Argentina : los colores de la mirada lingüística

El libro reúne trabajos en los que se exponen resultados de investigaciones presentadas por investigadores de Argentina, Chile, Brasil, España, Italia y Alemania en el XII Congreso de la Sociedad Argentina de Lingüística (SAL), Bicentenario: la renovación de la palabra, realizado en Mendoza, Argentina, entre el 6 y el 9 de abril de 2010. Las temáticas abordadas en los 167 capítulos muestran las grandes líneas de investigación que se desarrollan fundamentalmente en nuestro país, pero también en los otros países mencionados arriba, y señalan además las áreas que recién se inician, con poca tradición en nuestro país y que deberían fomentarse. Los trabajos aquí publicados se enmarcan dentro de las siguientes disciplinas y/o campos de investigación: Fonología, Sintaxis, Semántica y Pragmática, Lingüística Cognitiva, Análisis del Discurso, Psicolingüística, Adquisición de la Lengua, Sociolingüística y Dialectología, Didáctica de la lengua, Lingüística Aplicada, Lingüística Computacional, Historia de la Lengua y la Lingüística, Lenguas Aborígenes, Filosofía del Lenguaje, Lexicología y Terminología

Propuesta de mejora para la generación de un modelo de emisión y reemisión centralizado de tarjetas de crédito para un banco

Tesis (Ingeniero Civil Industrial)El presente trabajo, generará un beneficio económico al banco, contribuyendo en determinar los recursos necesarios, para mejorar la eficiencia en el proceso de emisión y reemisión de tarjetas de crédito, el cual, se debe canalizar según su demanda en las sucursales, así como también, disminución de la carga operativa de los ejecutivos de atención en las sucursales orientando sus labores a captación de nuevos clientes. Además, contribuye a optimizar el proceso actual, con la finalidad de encontrar, la cantidad de máquinas necesarias para satisfacer la demanda en relación con, lo que ha crecido el banco, y la reducción de gastos de la compañía por concepto de mantención mensual y gastos en insumos

Cognitive fitness of cost-efficient brain functional networks

The human brain's capacity for cognitive function is thought to depend on coordinated activity in sparsely connected, complex networks organized over many scales of space and time. Recent work has demonstrated that human brain networks constructed from neuroimaging data have economical small-world properties that confer high efficiency of information processing at relatively low connection cost. However, it has been unclear how the architecture of complex brain networks functioning at different frequencies can be related to behavioral performance on cognitive tasks. Here, we show that impaired accuracy of working memory could be related to suboptimal cost efficiency of brain functional networks operating in the classical β frequency band, 15–30 Hz. We analyzed brain functional networks derived from magnetoencephalography data recorded during working-memory task performance in 29 healthy volunteers and 28 people with schizophrenia. Networks functioning at higher frequencies had greater global cost efficiency than low-frequency networks in both groups. Superior task performance was positively correlated with global cost efficiency of the β-band network and specifically with cost efficiency of nodes in left lateral parietal and frontal areas. These results are consistent with biophysical models highlighting the importance of β-band oscillations for long-distance functional connections in brain networks and with pathophysiological models of schizophrenia as a dysconnection syndrome. More generally, they echo the saying that “less is more”: The information processing performance of a network can be enhanced by a sparse or low-cost configuration with disproportionately high efficiency

Supplement 1. CRECERIA: a program for estimating size-age relations.

<h2>File List</h2><blockquote> <p><a href="CRECERIAintro.htm">CRECERIAintro.htm</a> : Introduction, contrast of CRECERIA with CRECE, description, diagram, and example<br> <a href="CRECERIAmat.txt">CRECERIAmat.txt</a> : source code for MatLab<br> <a href="CRECERIAbas.txt">CRECERIAbas.txt</a> : source code for TurboBasic<br> <a href="CRECERIAdataFP.txt">CRECERIAdataFP.txt</a> : sample data file </p><p><a href="CRECERIA.zip">CRECERIA.zip</a> : All files at once<br> </p><p> </p></blockquote><h2>Description</h2><blockquote> <p>The program and its innovations are introduced in CRECERIAintro, which includes a diagram of the context and growth algorithm for CRECERIA and a test of the autocorrelation algorithm and sample results based on the sample data file. The source code is provided in two forms, for MatLab 6.1.0 and Basic (TurboBasic 1.0). The sample data (<i>n</i> = 76) are trunk diameter (mm) at 135 cm above ground in 1985 and 1991 for a canopy tree species of tropical deciduous forest, <i>Forchhammeria</i> <i>pallida</i> (Capparaceae) at Chamela (19°30'N  105°03'W), Jalisco, México, from individuals marked and measured by S. H. Bullock. All the files are based on Rodríguez-Navarro, J. L., and S. H. Bullock. 2003. CRECERIA: un programa que estima la relación tamaño-edad para aplicaciones en la biología. Informe Técnico 6493, Comunicaciones Académicas, Serie Ecología, CICESE, Ensenada, Baja California, México. The text of that report was translated and substantially reduced and modified for this Supplement, with permission from CICESE. </p> </blockquote> <br