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1	L-DOPA administration shifts the stability-flexibility balance towards attentional capture by distractors during a visual search task Riedel, P., Domachowska, I. M., Lee, Y., Neukam, P. T., Tönges, L., Li, S. C., Goschke, T., Smolka, M. N. 21 May 2024 (has links) Rationale The cognitive control dilemma describes the necessity to balance two antagonistic modes of attention: stability and flexibility. Stability refers to goal-directed thought, feeling, or action and flexibility refers to the complementary ability to adapt to an ever-changing environment. Their balance is thought to be maintained by neurotransmitters such as dopamine, most likely in a U-shaped rather than linear manner. However, in humans, studies on the stability-flexibility balance using a dopaminergic agent and/or measurement of brain dopamine are scarce. Objective The study aimed to investigate the causal involvement of dopamine in the stability-flexibility balance and the nature of this relationship in humans. Methods Distractibility was assessed as the difference in reaction time (RT) between distractor and non-distractor trials in a visual search task. In a randomized, placebo-controlled, double-blind, crossover study, 65 healthy participants performed the task under placebo and a dopamine precursor (L-DOPA). Using 18F-DOPA-PET, dopamine availability in the striatum was examined at baseline to investigate its relationship to the RT distractor effect and to the L-DOPA-induced change of the RT distractor effect. Results There was a pronounced RT distractor effect in the placebo session that increased under L-DOPA. Neither the RT distractor effect in the placebo session nor the magnitude of its L-DOPA-induced increase were related to baseline striatal dopamine. Conclusions L-DOPA administration shifted the stability-flexibility balance towards attentional capture by distractors, suggesting causal involvement of dopamine. This finding is consistent with current theories of prefrontal cortex dopamine function. Current data can neither confirm nor falsify the inverted U-shaped function hypothesis with regard to cognitive control. info:eu-repo/classification/ddc/610 ddc:610 info:eu-repo/classification/ddc/004 ddc:004
2	Country size, growth and the economic and monetary union Alouini, Olfa 12 June 2012 (has links) Der Zweck dieser Arbeit ist es, die Beziehung zwischen die Größe des Landes und das Wachstum auf internationaler Ebene und vergleichsweise in der Wirtschafts-und Währungsunion zu untersuchen und erarbeiten ihre Folgen für das Verhalten der wachstumsorientierte Finanzpolitik. Um ein globales Verständnis des Zusammenhangs zwischen Größe des Landes und das Wachstum in der EWU weiter verfolgen wir einen interdisziplinären Ansatz, einschließlich der makroökonomischen Modellierung (DSGE), Ökonometrie und Analyse der politischen Ökonomie. Die Kombination dieser Untersuchungen schließen wir, dass die Größe des Landes einen Einfluss auf die wirtschaftlichen Strukturen der Nationen, die Auswirkungen ihrer Politik und damit auf ihre Wachstumsdynamik hat. Aus diesem Grund ist es notwendig, die Bedeutung der Größe des Landes und ihre Folgen für die WWU wieder. / The purpose of this dissertation is to investigate the relationship between country size and growth at the international level and comparatively in the Economic and Monetary Union, and to draw up its consequences for the conduct of growth-orientated fiscal policies. To further a global understanding of the link between country size and growth in the EMU, we follow an interdisciplinary approach, including macro-economic modelling (DSGE), econometrics and political economy analysis. Combining these analyses, we conclude that country size has an incidence on the economic structures of nations, the effects of their policies and therefore on their pace of growth. For this reason there is a need to reinstate the importance of country size and its consequences for the EMU. Wachstum Heterogenität Währungsunion WWU Eurozone Europäischen Zentralbank Stabilitäts-und Wachstumspakt Fiskalpolitik Land Größe Hauptkomponentenanalyse Konjunktur Volatilität Politische Ökonomie Heterogeneity European Central Bank Growth EMU Eurozone Monetary union Stability and Growth Pact Fiscal policy Country size Principal component analysis Business cycle volatility Political economy 330 Wirtschaft 17 Wirtschaft QG 000 ddc:330

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L-DOPA administration shifts the stability-flexibility balance towards attentional capture by distractors during a visual search task

Country size, growth and the economic and monetary union