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Search Results: 1 - 10 of 176465 matches for " Marc E. Lavoie "
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How the Brain Process Stimulus-Response Conflict? New Insights from Lateralized Readiness Potentials Scalp Topography and Reaction Times  [PDF]
Marc E. Lavoie, Johannes E. A. Stauder
Journal of Behavioral and Brain Science (JBBS) , 2013, DOI: 10.4236/jbbs.2013.31014
Abstract:
Stimulus-Response Compatibility (SRC) refers to the fact that some tasks are performed easier and better than others because of the way stimuli and responses are paired with each other. To assess the brain responses to stimulus-response conflicts, we investigated the behavioral (accuracy and Reaction Times: RTs) as well as the physiological response (Lateralized Readiness Potentials: LRP) modulations in a positional blocked and a conditional mixed design in twelve university students. Results revealed that the performance was less accurate and the RTs, as well as the LRP onset, were delayed under the mixed conditional design. A greater compatibility effect was also noted on accuracy, RTs and LRP onset latency in the mixed design. Consistent with these findings, smaller peak activation at fronto-central areas suggests that more selective inhibition is needed in a mixed design context. Despite a smaller activation, the topographical distribution is similar in both designs. These results indicate that the translation time between stimulus- and response codes are greater under the mixed instruction, while the similar LRP topography suggests that common neural structures underlie LRPs in response to both type of designs.
Effect of emotional valence on episodic memory stages as indexed by event-related potentials  [PDF]
Marc E. Lavoie, Kieron P. O’Connor
World Journal of Neuroscience (WJNS) , 2013, DOI: 10.4236/wjns.2013.34034
Abstract:

Several investigations have shown that emotional events show superior recall than non-emotional ones. However, the cortical mechanisms underlying the episodic recall of emotional scenes are still poorly understood. Our main aim was to compare the magnitude of the Event-Related brain Potentials (ERP) old-new effect related to emotionally unpleasant, pleasant and neutral photographic images. As expected, correct recognition of all types of images elicited three topographically distinct ERP components sensitive to the classical old-new recognition effect. The results revealed that the behavioral performances were mainly sensitive to arousal, while the ERP old/new effect over posterior regions (300 - 1000 ms) was exclusively affected by unpleasantness. A later component (1000 - 1400 ms) showed an inverted old/ new effect at parietal sites, which was also sensitive to unpleasantness. These results imply that ERP reflecting episodic conscious recollection and post-retrieval monitoring are clearly affected both by valence and arousal.

Cognitive Aspects of Hyperactivity and Overactivity in Preadolescents with Tourette Syndrome
Anick Laverdure,Kieron O'Connor,Marc E. Lavoie
Psychiatry Journal , 2013, DOI: 10.1155/2013/198746
Abstract: Attention deficit disorder with hyperactivity (ADHD) is a common comorbidity in children with Tourette syndrome (TS). However, motor restlessness and high levels of sensorimotor activation or “overactivity” may be a feature of TS rather than a distinct ADHD comorbidity. The link between overactivity and ADHD in TS has yet to be established and in particular between adult and preadolescent manifestations. The current study furthers this understanding of ADHD features in TS by investigating the relationship between cognitive and behavioral aspects of ADHD and TS. The style of planning (STOP) overactivity scale was compared in preadolescent ( ) and adult ( ) samples. The STOP overactivity scale measures the characteristic overactive style of planning in everyday life. The aims of the study were twofold as follows: (1) to see if an overactive style was present in adolescents as well as in adults, and (2) to see if this overactive style correlated with hyperactivity, impulsivity, or perfectionism. Results suggest that overactivity may be a better description of the hyperactivity manifestations in TS. Behavioral components of overactivity were present in preadolescents while the cognitive components were more frequent in adults. Overactivity relates at the same time to perfectionism and impulsivity. 1. Introduction Tourette syndrome (TS) is a tic disorder characterized by the presence of at least one phonic tic and several motor tics for 3 consecutive months (American Psychiatric Association [1]. A tic is defined as an involuntary, sudden, repetitive and stereotyped movement or vocalization. TS has to be diagnosed before the age of 18 and is more frequent in males than in females (1.5?:?1 to 3?:?1) [2–6] TS is present in 5 to 30 children and in 1 to 2 adults on 10?000 [1]. Over the last decade, many epidemiological studies have tried to establish a more representative prevalence rate of TS [7–11], and the prevalence rate of TS is estimated now to be one individual in 200 [12]. Rates of comorbidity vary across studies and estimates between 50% and 90% of children with TS have sufficient behavioral and emotional symptoms to meet diagnostic criteria for a comorbid disorder [13, 14]. In most cases, the externalized manifestations of these comorbid disorders may be more disruptive than the tics per se and can often be the main motivator for seeking help [12]. The disorders most frequently associated with TS are attention deficit disorder with hyperactivity (ADHD), obsessive-compulsive disorder (OCD), anxiety and mood disorders, behavioral disorders, and learning
¿Las teorías heterodoxas tienen algo en común? Un punto de vista postkeynesiano
Lavoie,Marc;
Lecturas de Economía , 2005,
Abstract: this article presents different theoretical elements that share some heterodox ideas. these elements reside in four intricate areas: rationality of the individual, the theory of prices, the kaleckian model of growth, and the integration of the real with the monetary sector. despite the divergences, these theoretical elements constitute a coherent set that could be improved with the aim of building a sole heterodox theory, which would serve as a real alternative to the dominant neoclassical theory.
Are we all Keynesians?
Lavoie, Marc;
Revista de Economia Política , 2010, DOI: 10.1590/S0101-31572010000200001
Abstract: this essay asks whether we are all becoming keynesians again. it offers some thoughts about the impact of the financial crisis on macroeconomic theory and keynesian theory, and on post-keynesian theory in particular. it is argued that the crisis does have obvious effects on how keynesianism is being perceived by decision makers, and that some effects are also observed on academia. however, there are forces within the economics profession and the population at large which are resistant to this second coming of the keynesian revolution.
Las teorías heterodoxas tienen algo en común? Un punto de vista postkeynesiano
Marc Lavoie
Lecturas de Economía , 2005,
Abstract: Este artículo presenta los diferentes elementos teóricos que comparten algunas corrientes heterodoxas. Estos elementos se encuentran al interior de cuatro grandes problemáticas: la racionalidad de los individuos, la teoría de los precios, el modelo kaleckiano de crecimiento y la integración del sector real con el sector monetario. A pesar de las divergencias, estos elementos teóricos constituyen un conjunto coherente que podría ser mejorado con el ánimo construir una única teoría heterodoxa, la cual serviría de verdadera alternativa a la teoría neoclásica dominante.
La ense anza de Economía post-Keynesiana en un departamento ortodoxo
Marc Lavoie
Revista de Economía Crítica , 2011,
Abstract:
Exercise Intensity Modulation of Hepatic Lipid Metabolism
Fábio S. Lira,Luiz C. Carnevali Jr,Nelo E. Zanchi,Ronaldo VT. Santos,Jean Marc Lavoie,Marília Seelaender
Journal of Nutrition and Metabolism , 2012, DOI: 10.1155/2012/809576
Abstract: Lipid metabolism in the liver is complex and involves the synthesis and secretion of very low density lipoproteins (VLDL), ketone bodies, and high rates of fatty acid oxidation, synthesis, and esterification. Exercise training induces several changes in lipid metabolism in the liver and affects VLDL secretion and fatty acid oxidation. These alterations are even more conspicuous in disease, as in obesity, and cancer cachexia. Our understanding of the mechanisms leading to metabolic adaptations in the liver as induced by exercise training has advanced considerably in the recent years, but much remains to be addressed. More recently, the adoption of high intensity exercise training has been put forward as a means of modulating hepatic metabolism. The purpose of the present paper is to summarise and discuss the merit of such new knowledge.
Exercise Intensity Modulation of Hepatic Lipid Metabolism
Fábio S. Lira,Luiz C. Carnevali Jr,Nelo E. Zanchi,Ronaldo VT. Santos,Jean Marc Lavoie,Marília Seelaender
Journal of Nutrition and Metabolism , 2012, DOI: 10.1155/2012/809576
Abstract: Lipid metabolism in the liver is complex and involves the synthesis and secretion of very low density lipoproteins (VLDL), ketone bodies, and high rates of fatty acid oxidation, synthesis, and esterification. Exercise training induces several changes in lipid metabolism in the liver and affects VLDL secretion and fatty acid oxidation. These alterations are even more conspicuous in disease, as in obesity, and cancer cachexia. Our understanding of the mechanisms leading to metabolic adaptations in the liver as induced by exercise training has advanced considerably in the recent years, but much remains to be addressed. More recently, the adoption of high intensity exercise training has been put forward as a means of modulating hepatic metabolism. The purpose of the present paper is to summarise and discuss the merit of such new knowledge. 1. Introduction Lipid metabolism involves numerous pathways that are, at least partly, interdependent. The lipid available for liver uptake may derive from the diet [1] or from mobilisation of fatty acids (FAs) from the adipose tissue, followed by the transport in the circulation, [2], which requires specific transporters such as albumin, while diet lipids in the form of triacylglycerol (TG) are transported by chylomicra and very low density lipoprotein (VLDL). In the liver, specific transporters (FAT and L-FABP) are involved in the uptake and intracellular traffic of these molecules [3, 4]. The hepatocyte then carries out TG hydrolysis to diacylglycerol (performed by microsomal lipase) and then to fatty acids, which are then activated and combined with coenzyme A, allowing their transport into the reticulum luminal space by intraluminal carnitine acyltransferase, where they are again esterified by TG diacylglycerol acyltransferase 2 [5], and become a part of nascent hepatic VLDL, or are stored within lipid droplets. Long-chain fatty acids (LCFA) deriving from exogenous sources or from intracellular pools may conversely be totally or partially oxidised by the hepatocyte mitochondria, a process that requires the action of an enzyme system, the carnitine palmitoyltransferases, and the channelling of the fatty acyl to either ketone body production or to B-oxidation. Finally, other possible fates of LCFA include the modification of the molecule, yielding, for instance, cholesterol and the incorporation into components of the cells, as into the membrane phospholipids [6]. The final fate of LCFA in the liver depends on a plethora of factors, including the quantity and type of fatty acid, hormonal regulation, contribution of
The impact of birch seedlings on evapotranspiration from a mined peatland: an experimental study in southern Quebec, Canada
E. Fay,C. Lavoie
Mires and Peat , 2009,
Abstract: Dense stands of birch (Betula spp.) on abandoned peat workings have often been identified as potential barriers to site restoration, but little research has been conducted to evaluate their impact on water resources. The objective of this experimental study was to determine whether birch seedlings established on an abandoned mined peatland in eastern Canada had a significant impact on evapotranspiration. Transpiration rates from birch seedlings planted in containers filled with Sphagnum compost were measured gravimetrically. Unplanted containers were used to similarly measure evaporation rates from bare peat. On average, the measured rates of evaporation (per unit area) from peat were 2.5 times the rates of transpiration from birch leaves. However, if the total leaf area of a dense birch population established on an abandoned mined peatland is considered, the total amount of water lost through birch transpiration could be higher than that lost by evaporation from the peat surface. This study provides a rough estimate of potential water losses due to birch seedling transpiration, and indicates that a dense population of birch on a mined peatland may influence site hydrology even at the early establishment phase (seedlings). Consequently, recently abandoned mined peatlands should be restored rapidly to prevent the establishment of birch trees.
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