References of "Quertemont, Etienne"
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See detailChronic tolerance to ethanol-induced sedation: Implication for age-related differences in locomotor sensitization
Quoilin, Caroline; Didone, Vincent ULg; Tirelli, Ezio ULg et al

in Alcohol (2013), 47(4), 317-322

The adolescent brain has been suggested to be particularly sensitive to ethanol-induced neuroadaptations, which in turn could increase the risk of youths for alcohol abuse and dependence. Sensitization to ... [more ▼]

The adolescent brain has been suggested to be particularly sensitive to ethanol-induced neuroadaptations, which in turn could increase the risk of youths for alcohol abuse and dependence. Sensitization to the locomotor stimulant effects of ethanol has often been used as an animal model of ethanol-induced neuroadaptations. Previously, we showed that young mice were more sensitive than adults to the locomotor sensitization induced by high ethanol doses. However, this effect could be due to age-related differences in chronic tolerance to the sedative effects of ethanol. The aim of the present study is to assess chronic tolerance to the sedative effects of ethanol in weaning 21-day-old (P21), adolescent 35-day-old (P35) and adult 63-day-old (P63) female Swiss mice. After a daily injection of saline or 4 g/kg ethanol during 6 consecutive days, all P21, P35 and P63 mice were injected with 4 g/kg ethanol and submitted to the loss of righting reflex procedure. Our results confirm that the sensitivity to the acute sedative effects of ethanol gradually increases with age. Although this schedule of ethanol injections induces significant age-related differences in ethanol sensitization, it did not reveal significant differences between P21, P35 and P63 mice in the development of a chronic ethanol tolerance to its sedative effects. The present results show that age-related differences in the development of ethanol sensitization cannot be explained by differences in chronic ethanol tolerance to its sedative effects. More broadly, they do not support the idea that ethanol-induced sensitization is a by-product of chronic ethanol tolerance. [less ▲]

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See detailAge-Related Differences in Perceptuomotor Procedural Learning in Children
Lejeune, Caroline ULg; Catale, Corinne ULg; Schmitz, Xavier ULg et al

in Journal of Experimental Child Psychology (2013), 116

Procedural learning is generally considered to proceed in a series of phases, with cognitive resources playing an important role during the initial step. From a developmental perspective, little is known ... [more ▼]

Procedural learning is generally considered to proceed in a series of phases, with cognitive resources playing an important role during the initial step. From a developmental perspective, little is known about the development of procedural learning or the role played by explicit cognitive processes during learning. The main objectives of this study were: (1) to determine whether procedural learning performance improves with age by comparing groups of 7-yearold children, 10-year-old children, and adults, and (2) to investigate the role played by executive functions during the acquisition in these three age groups. Seventy-six subjects were assessed on a computerized adaptation of the mirror tracing paradigm. Results revealed that the youngest children had more difficulty adapting to the task (they were slower and committed more errors at the beginning of the learning process) than 10-year-olds, but despite this age effect observed at the outset, all children improved performance across trials and transferred their skill to a different figure as well as adults. Correlational analyses showed that inhibition abilities play a key role in the performance of 10-year-olds and adults at the beginning of the learning, but not in 7-year-olds. Overall, our results suggest that the age-related differences observed in our procedural learning task are at least partly due to the differential involvement of inhibition abilities, which may facilitate (so long as they are sufficiently developed) learning in the initial steps of learning process; however, they would not be a necessary condition for skill learning to occur. [less ▲]

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See detailLes drogues dites "douces": cannabis et syndrome amotivationnel
Schmits, Emilie ULg; Quertemont, Etienne ULg

in Revue Médicale de Liège (2013), 68

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See detailChronic ethanol exposure during adolescence alters the behavioral responsiveness to ethanol in adult mice
Quoilin, Caroline ULg; Didone, Vincent ULg; Tirelli, Ezio ULg et al

in Behavioural Brain Research (2012), 229

Alcohol exposure during early adolescence is believed to durably alter the behavioral properties of ethanol, increasing the likelihood of later alcohol-related disorders. The aim of the present ... [more ▼]

Alcohol exposure during early adolescence is believed to durably alter the behavioral properties of ethanol, increasing the likelihood of later alcohol-related disorders. The aim of the present experiments was to characterize changes in the behavioral effects of ethanol in adult female Swiss mice after a chronic ethanol exposure during adolescence, extending from postnatal day 28 to postnatal day 42. After a chronic ethanol exposure during adolescence (daily injections of 0, 2.5 or 4 g/kg ethanol for 14 consecutive days), adult mice were tested at postnatal day 63. The locomotor stimulant effects of ethanol, together with ethanol sensitization were tested in experiment 1. In experiment 2, the sedative effects of ethanol were assessed with the loss of righting reflex procedure. Finally, in experiment 3, the anxiolytic effects of ethanol were tested with the light/dark box test. Adult mice chronically exposed to ethanol during adolescence showed a lower basal locomotor activity, but higher locomotor stimulant effects of ethanol than non-exposed mice. Additionally, these adult mice developed higher rates of ethanol sensitization after chronic re-exposure to ethanol in adulthood. Adult mice exposed to ethanol during adolescence also had a stronger tolerance to the sedative effects of high ethanol doses, although they showed no evidence of changes in the anxiolytic effects of ethanol. These results are in agreement with the thesis that chronic alcohol consumption during adolescence, especially in high amounts, increases the risk of later alcohol-related disorders. [less ▲]

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See detailDevelopmental differences in ethanol-induced sensitization using postweanling, adolescent, and adult Swiss mice
Quoilin, Caroline ULg; Didone, Vincent ULg; Tirelli, Ezio ULg et al

in Psychopharmacology (2012), 219

Rationale: The maturing adolescent brain has been suggested to be more sensitive than the adult brain to ethanol-induced neuroadaptations. In animal studies, sensitization to the stimulant effects of ... [more ▼]

Rationale: The maturing adolescent brain has been suggested to be more sensitive than the adult brain to ethanol-induced neuroadaptations. In animal studies, sensitization to the stimulant effects of ethanol is used to study the vulnerability to chronic ethanol-induced neurobehavioral alterations. Objectives: The aim of the present study was to systematically characterize age-dependent changes in the development and expression of the sensitization to the stimulant effects of a range of ethanol doses in female Swiss mice. Three ages were studied: 21-day-old mice (postweanlings), 35-day-old mice (adolescents), and 63-day-old mice (adults). Methods: Postweanling, adolescent, and adult mice were daily injected with saline or various ethanol doses (1.5 to 4 g/kg) for 7 days. They were then tested for acute and sensitized locomotor activity. Results: Postweanling and adolescent mice were more sensitive than adult mice to the acute stimulant effects of ethanol. In adult mice, daily injections of ethanol at doses between 2.5 and 4 g/kg led to significant sensitization. Higher ethanol doses (3.5 and 4 g/kg) were required to induce sensitization in postweanling and adolescent mice. However, younger mice showed ethanol sensitization of higher magnitude. Conclusions: Young mice develop very strong ethanol sensitization at doses that mimic binge drinking in humans. These results might explain why early ethanol drinking during adolescence is related to a higher prevalence of subsequent alcohol disorders. [less ▲]

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See detailSocial context in school: Its relation to adolescents' depressive mood
Boulard, Aurore ULg; Quertemont, Etienne ULg; Gauthier, Jean-Marie ULg et al

in Journal of Adolescence (2012), 35(1), 143-152

This study examined the impact of various school-related factors on adolescents’ depressive mood, including prosocial behavior, verbal aggression, and relationships with teachers. The data used in this ... [more ▼]

This study examined the impact of various school-related factors on adolescents’ depressive mood, including prosocial behavior, verbal aggression, and relationships with teachers. The data used in this study were collected in the context of a larger survey on victimization in secondary schools from the French Community of Belgium. Participants were 2896 secondary school students (1520 males; 1376 females) aged 12–18 years. Results showed that for both genders, the three strongest predictors of depressive mood were age, feeling of exclusion, and verbal aggression. This study focusing on school-related predictors of depressive mood confirmed the importance of the social context in school as a predictor of depression in both girls and boys. [less ▲]

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See detailDifferential Effects of Cocaine on Dopamine Neuron Firing in Awake and Anesthetized Rats
Koulchitsky, Stanislav ULg; DE BACKER, Benjamin ULg; Quertemont, Etienne ULg et al

in Neuropsychopharmacology : Official Publication of the American College of Neuropsychopharmacology (2012), 37

Cocaine (benzoylmethylecgonine), a natural alkaloid, is a powerful psychostimulant and a highly addictive drug. Unfortunately, the relationships between its behavioral and electrophysiological effects are ... [more ▼]

Cocaine (benzoylmethylecgonine), a natural alkaloid, is a powerful psychostimulant and a highly addictive drug. Unfortunately, the relationships between its behavioral and electrophysiological effects are not clear. We investigated the effects of cocaine on the firing of midbrain dopaminergic (DA) neurons, both in anesthetized and awake rats, using pre-implanted multielectrode arrays and a recently developed telemetric recording system. In anesthetized animals, cocaine (10 mg/kg, intraperitoneally) produced a general decrease of the firing rate and bursting of DA neurons, sometimes preceded by a transient increase in both parameters, as previously reported by others. In awake rats, however, injection of cocaine led to a very different pattern of changes in firing. A decrease in firing rate and bursting was observed in only 14% of DA neurons. Most of the other DA neurons underwent increases in firing rate and bursting: these changes were correlated with locomotor activity in 52% of the neurons, but were uncorrelated in 29% of them. Drug concentration measurements indicated that the observed differences between the two conditions did not have a pharmacokinetic origin. Taken together, our results demonstrate that cocaine injection differentially affects the electrical activity of DA neurons in awake and anesthetized states. The observed increases in neuronal activity may in part reflect the cocaine-induced synaptic potentiation found ex vivo in these neurons. Our observations also show that electrophysiological recordings in awake animals can uncover drug effects, which are masked by general anesthesia. [less ▲]

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See detailHow to Statistically Show the Absence of an Effect
Quertemont, Etienne ULg

in Psychologica Belgica (2011), 51(2), 109-127

In experimental studies, the lack of statistical significance is often interpreted as the absence of an effect. Unfortunately, such a conclusion is often a serious misinterpretation. Indeed, non ... [more ▼]

In experimental studies, the lack of statistical significance is often interpreted as the absence of an effect. Unfortunately, such a conclusion is often a serious misinterpretation. Indeed, non-significant results are just as often the consequence of an insufficient statistical power. In order to conclude beyond reasonable doubt that there is no meaningful effect at the population level, it is necessary to use proper statistical techniques. The present article reviews three different approaches that can be used to show the absence of a meaningful effect, namely the statistical power test, the equivalence test, and the confidence interval approach. These three techniques are presented with easy to understand examples and equations are given for the case of the two-sample t-test, the paired-sample t-test, the linear regression coefficient and the correlation coefficient. Despite the popularity of the power test, we recommend using preferably the equivalence test or the confidence interval. [less ▲]

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See detailStimulant effects of ethanol in adolescent Swiss mice: development of sensitization and consequences in adulthood
Quoilin, Caroline ULg; Didone, Vincent ULg; Quertemont, Etienne ULg

in Alcohol & Alcoholism (2011), 46(Supplément 1), 40

The adolescent period is characterized by behavioral and neurobiological changes, which might predispose adolescents to the long-term negative consequences of alcohol. For example, enhanced risks of ... [more ▼]

The adolescent period is characterized by behavioral and neurobiological changes, which might predispose adolescents to the long-term negative consequences of alcohol. For example, enhanced risks of alcohol dependence are reported when drinking is initiated early. In the present studies, we used Swiss female mice to test whether chronic ethanol injections during adolescence durably affect the sensitivity to the stimulant effects of ethanol in adulthood. In a first set of experiments, several groups of young (28 day-old) mice were daily injected with various ethanol doses (1.5 – 4 g/kg) to test for ethanol sensitization during adolescence in comparison to adult mice exposed to the same schedule of ethanol injections. The results show that young mice express much higher stimulant effects after acute ethanol injections. However, they also require higher ethanol doses than adult mice to develop a sensitization to the stimulant effects of ethanol. In a second set of experiments, 28 day-old mice were sensitized to ethanol for 14 days with high ethanol doses (2.5 or 4 g/kg) and then tested for the stimulant effects of ethanol and the development of ethanol sensitization in adulthood. The results of this second set of experiments show that mice sensitized to ethanol during their adolescence remain more sensitive to the acute stimulant effects of ethanol in adulthood, especially when high ethanol doses were administered. However, the rate of the development of a sensitization to this effect was only slightly affected relative to adult mice exposed to a chronic ethanol regimen for the first time. Together, these results indicate that adolescent mice are more sensitive to the stimulant effects of ethanol but require higher ethanol doses to develop a sensitization. However, when a sensitization develops during adolescence, these mice still experience higher ethanol stimulant effects when tested in adulthood. [less ▲]

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See detailDo excitatory and inhibitory conditioning processes underlie psychomotor sensitization to amphetamine? An analysis using simple and multiple regressions
Brabant, Christian ULg; Tambour, Sophie; Quertemont, Etienne ULg et al

in Behavioural Brain Research (2011), 221

Excitatory or inhibitory conditioning processes have been proposed to account for the context-dependent establishment of amphetamine psychomotor sensitization in rodents. The purpose of this study was to ... [more ▼]

Excitatory or inhibitory conditioning processes have been proposed to account for the context-dependent establishment of amphetamine psychomotor sensitization in rodents. The purpose of this study was to test the predictions of these theories in mice. We first assessed the consequence of the extinction of post-sensitization conditioned activity (CR) on the ulterior expression of sensitization. We also assessed the relations between several measures of sensitization and conditioned hyperactivity revealed on a saline challenge using simple and multiple regression analyses. Context-dependent sensitization was induced via 7 amphetamine injections in the test context given alternately with 7 saline injections in another context in paired mice, unpaired mice receiving the converse pretreatment. Context-dependent sensitization (drug challenge) and the CR (saline challenge) were revealed subsequently. After CR extinction (over 7 every-other-day repetition of the saline challenge), mice were tested again for context-dependent sensitization. Against the excitatory conditioning model, CR extinction spared context-dependent sensitization in paired mice, and regression analyses revealed no significant correlations between the size of the CR and several measures of sensitization. In apparent agreement with the inhibitory conditioning model, unpaired mice expressed higher levels of sensitization in the test context after extinction than before. However, regression analyses did not indicate that activity on the saline challenge was related to measures of sensitization in unpaired mice. Therefore, the present results support neither the excitatory nor the inhibitory conditioning models of context-dependent sensitization, but remain compatible with theories proposing that other inhibitory mechanisms modulate sensitization. [less ▲]

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See detailDu corps à la parole
Close, Mireille; Servais, Catherine; Quertemont, Etienne ULg et al

in Revue des Hôpitaux de Jour Psychiatriques et des Thérapies Institutionnelles (2011), 14

Through an interactive workshop called "the feelings through the senses", we are going to describe three successive stages allowing to tame the psychic experiences via the sensory channels, the hearing ... [more ▼]

Through an interactive workshop called "the feelings through the senses", we are going to describe three successive stages allowing to tame the psychic experiences via the sensory channels, the hearing then the sight, isolated artificially at first then gathered secondly. A work of verbalization in small groups is realized at the end of every session. To test the emotional changes among our patients benefiting from this institutional psychotherapy, we have been assessing, for two years, for every patient, at the beginning and the end of hospitalization, the following dimensions: awareness of feelings, representation of emotions, capacities of social regulation of the feelings. These first results are encouraging and testify that the therapeutic work in institution enhances transfer and counter- transfer movements by leading new corrective emotional experiences in a "secure" environment. The Day hospital, transformer of psychic experiences, proves to be a real process of particularly dynamic symbolization... [less ▲]

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See detailGradual changes in the sensitivity to the stimulant and sedative effects of ethanol during adolescence in Swiss mice
Quoilin, Caroline ULg; Didone, Vincent ULg; Quertemont, Etienne ULg

in Alcoholism, Clinical & Experimental Research (2010), 34(8), 97-97

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See detailOntogeny of the stimulant and sedative effects of ethanol in male and female Swiss mice: gradual changes from weaning to adulthood
Quoilin, Caroline ULg; Didone, Vincent ULg; Tirelli, Ezio ULg et al

in Psychopharmacology (2010), 212(4), 501-512

Rationale: The adolescent period is characterized by a specific sensitivity to the effects of alcohol, which is believed to contribute to the enhanced risks of alcohol dependence when drinking is ... [more ▼]

Rationale: The adolescent period is characterized by a specific sensitivity to the effects of alcohol, which is believed to contribute to the enhanced risks of alcohol dependence when drinking is initiated early during adolescence. In adolescent rodents, while the reduced sensitivity to the sedative effects of ethanol has been well characterized, its stimulant effects have not yet been extensively studied. Objectives: The present study characterized the development of the stimulant and sedative effects of acute ethanol in male and female Swiss mice from weaning to early adulthood and tested whether both effects are interrelated. Methods: In a first experiment, mice aged 21, 28, 35, 42 and 60 days were injected with various ethanol doses and tested for ethanol-induced locomotor activity. In an independent experiment, mice of the same groups of age were injected with 4 g/kg ethanol and ethanol-induced sedation was quantified with the loss of righting reflex procedure. Results: In male and female mice, the stimulant effects of ethanol gradually decreased, whereas its sedative effects increased with age. When the sedation was statistically controlled using a covariance analysis, the differences between adult and juvenile mice in the locomotor stimulation were significantly reduced. Conclusions: From weaning to early adulthood, the acute stimulant and sedative effects of ethanol show gradual changes that are similar in male and female mice. Although the initial tolerance to the sedative effects of ethanol contribute to the changes in ethanol-induced locomotor activity, young mice also show a higher sensitivity to the stimulant effects of ethanol. [less ▲]

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See detailAnxiety in adult female mice following perinatal exposure to chlorpyrifos.
Braquenier, Jean-Baptiste; Quertemont, Etienne ULg; Tirelli, Ezio ULg et al

in Neurotoxicology & Teratology (2010), 32

Epidemiologic studies suggested a possible link between prenatal exposure to organophosphate insecticides (OP) and long-term mental delay and some behavioral troubles. Experimental studies in rats and ... [more ▼]

Epidemiologic studies suggested a possible link between prenatal exposure to organophosphate insecticides (OP) and long-term mental delay and some behavioral troubles. Experimental studies in rats and mice have confirmed that a relatively short exposure to low doses of OP such as chlorpyrifos (CPF) during specific perinatal periods decreased anxiety-like behaviors. In the present study, we report that chronic perinatal exposure (GD15-PND14) to low doses of CPF leads to an increase (and not a decrease) in anxiety-like behaviors of female mouse offspring. Pregnant or lactating female mice were exposed to CPF (0.2; 1; or 5 mg/kg day) by oral treatment during 18 consecutive days. Following a recovery period of several weeks, the anxiety of adult female offspring was determined using neurobehavioral tests (elevated plus-maze and light/dark box tests). Our results showed that CPF-exposed female offspring were more anxious than controls. In addition, the magnitude of anxiety profile alterations depended on the level of exposure to CPF during gestation and lactation with a maximal effect observed at the 1 mg/kg day dose. Our results confirm that OP exposure during the perinatal period can induce long-term alterations in mouse anxiety-like behaviors and suggest that the routes of administration and the duration of OP exposure during brain development may be factors to consider when studying the development of anxiety. [less ▲]

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See detailEffects of brand presence and stimulus of comparison on response inhibition toward alcohol cues in male and female heavy drinkers
Kreusch, Fanny ULg; Quertemont, Etienne ULg

in 2010 annual meeting of the Belgian Association for Psychological Sciences (2010)

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