Rationale. Adolescence may be a period of susceptibility to the effects of drugs of abuse. This vulnerability may result from a convergence of psychological processes that contribute to drug addiction including impulsive action and incentive motivation during adolescence. Objectives. I examined age differences in incentive motivation, as measured by responding for a conditioned reinforcer (CR) previously paired with natural or drug rewards, and age and sex differences in impulsive action, as measured by responding on a differential reinforcement of low rates of responding (DRL) schedule or premature responding on the 2-Choice Serial Reaction Time Test (2-CSRTT), in Sprague-Dawley rats. The effects of drugs that affect these behaviours in adulthood and that act on neurochemical systems still developing during adolescence were also examined. Methods. In a first set of experiments (Chapter 3), I compared male adolescents and adults on responding for a CR previously paired with sucrose and the effect of amphetamine on this behaviour. In a second set of experiments (Chapter 4), I examined age differences in responding for a CR previously paired with passive or self-administered intravenous (IV) nicotine infusions. Subsequently, I investigated age and sex differences in responding on a DRL schedule in response to amphetamine (Chapter 5) and 2-CSRTT performance in response to amphetamine, nicotine and Ro 63-1908 (a glutamate N-Methyl-D-aspartic acid [NMDA] receptor subunit antagonist; Chapter 6). Results. Compared to adults, adolescents responded more for a CR previously paired with sucrose or passive, but not self-administered, IV nicotine infusions. Amphetamine only enhanced responding for a CR previously paired with sucrose. Adolescents responded more than adults on a DRL schedule, while adolescents made the most premature responses in the 2-CSRTT. No consistent sex differences were observed during the acquisition of either behaviour. Amphetamine increased premature responding most in adolescent males and adult females in the 2-CSRTT but not in responding on the DRL schedule. No consistent age or sex differences were observed for Ro 63-1908 or nicotine. Conclusions. Adolescents show enhanced impulsivity and incentive motivation than adults depending on the behavioural measure. Dopamine may contribute to age and sex differences in these behaviours.

Chez l’espèce humaine comme pour de nombreuses autres espèces animales, lorsque des stimuli environnementaux précèdent de façon régulière la présentation d’événements importants pour un individu, ces stimuli vont acquérir sous certaines conditions la capacité à évoquer des comportements dits d’anticipation. Cette capacité est considérée par de nombreux auteurs comme ayant une haute valeur adaptative, favorisant le contact avec des événements appétitifs et permettant l’évitement d’événements aversifs. Ces dernières décennies, deschercheurs ont initié un rapprochement entre le phénomène d’anticipation et le conditionnement Pavlovien. Ce rapprochement repose à la fois sur une similarité dans les caractéristiques des événements mis en jeux mais surtout sur de nombreux effets et phénomènes semblables, amenant ces auteurs à considérer que les comportements ditsd’anticipation, d’une façon générale, reposeraient sur le processus Pavlovien. Leconditionnement Pavlovien offre une littérature extrêmement riche dont l’une des principalesquestions de recherche concerne le problème des conditions à l’apparition du processus.Parmi les hypothèses existantes, l’Hypothèse de l’Information est sans aucun doute l’une desplus importantes par son influence. Selon cette hypothèse, un apprentissage associatifPavlovien n’aura lieu que lorsqu’un événement important sera présenté de façon inattendu à un sujet, et l’apprentissage, ou les associations apprises, ne porteront que sur des stimuli prédictifs de l’événement important (i.e. permettant son anticipation). A travers deux expériences appliquant une procédure de conditionnement rétrograde à une procédure de renforcement conditionné, nous avons cherché à tester les propositions faites par cette hypothèse. Nos résultats vont directement à l’encontre de ces propositions et vont au contraire dans le sens de deux autres propositions théoriques faites sur le conditionnement Pavlovien,illustrées par le modèle SOP et l’Hypothèse du Codage Temporel. Ces deux propositions sont testées au sein d’une troisième et dernière expérience, dont les implications pour ces modèles comme pour la conceptualisation du conditionnement Pavlovien et de l’anticipation de façon générale sont discutées. / In human and non-human animals, environmental stimuli that reliably accompany the presentation of significant events are able after repeated exposures of eliciting anticipatory behaviors. Many authors underlined the adaptive value of anticipatory responses, and suggested a connection with Pavlovian conditioning. Linking anticipatory behaviors to Pavlovian conditioning is supported by the similarity in procedure (i.e. a pairing between a neutral stimulus with a significant event), but also on the common effects and phenomena, and the authors assume that Pavlovian conditioning is the process underlying the anticipation of events. This assumption is at the heart of the Information Hypothesis, and more generally of a functional and predictive perspective of Pavlovian conditioning. According to the Information Hypothesis, Pavlovian conditioning only occurs when an unexpected significant event is presented, and learning (i.e. the formation of association) would be about stimuli that allow the anticipation of the significant event. Using a backward conditioning procedure in a conditioned reinforcement preparation, we tested the assumptions made by the Information Hypothesis. The results found argue against the Information Hypothesis and, in contrast, support the assumption made by two others types of leaning models, illustrated by the Temporal Coding Hypothesis and the SOP model. The Temporal Coding Hypothesis and SOP are tested in a third experiment. Implications for Pavlovian conditioning models and anticipatory behaviors in general are discussed.

Made available in DSpace on 2016-04-29T13:17:57Z (GMT). No. of bitstreams: 1 Marcelo Correa Abuchacra.pdf: 903654 bytes, checksum: bd2be7d5bb3d97ab8913c4f3dc3024c3 (MD5) Previous issue date: 2016-01-26 / The present study aims to investigate the influence of a conditioned reinforcement on the performance of base categories soccer players at the behavior of completion of the goal. To measure the accuracy of the kicks, the goal will be divided into four targets (lower right, lower left, upper right and upper left), according to the Battery of tests Mor-Christian. . Investigation of the performance of the participants will be held through a multiple base line design, consisting of a baseline and a subsequent step of conditioned reinforcement. At the end of the sections in the second phase, the participants can exchange the points accumulated on the task for money. Data obtained by each participant in each stage of the research will be analyzed and compared, in order to check the influence of the conditioned reinforcement on the performance of participants regarding the amount of hits to established targets / O presente trabalho tem por objetivo investigar a influência de um reforço condicionado sobre a precisão do comportamento de "chute no gol" em jogadores de futebol em formação. Para medir a precisão dos chutes, o gol será dividido em quatro alvos (inferior direito, inferior esquerdo, superior direito e superior esquerdo) de acordo com a "Bateria de testes de Mor-Christian . O experimento compreenderá duas fases: 1) linha de base e 2) reforço condicionado. Na fase do reforço condicionado, será empregado um delineamento de base múltipla entre os alvos. Ao final das sessões realizadas na etapa dois, os participantes poderão trocar os pontos acumulados na tarefa por dinheiro. Os dados obtidos por cada participante, em cada etapa da pesquisa, serão analisados e comparados entre si, com o objetivo de verificar a influência do reforço condicionado no desempenho dos participantes em relação a quantidade de acertos aos alvos estabelecidos

Made available in DSpace on 2016-04-29T13:18:02Z (GMT). No. of bitstreams: 1 Paulo A B Panetta.pdf: 2725022 bytes, checksum: 647e2f895cbc2bf81fd00346a8f0e9ab (MD5) Previous issue date: 2007-05-07 / Fifteen rats were randomized to one of the five following groups (with three rats in each group) to examine the effects of different durations of light ( delay signal ) upon the response acquisition and maintenance of lever press with delayed reinforcement, on the absence of shaping. Two phases construct the experiment, with fifteen experimental sessions and two sessions in extinction on each phase. For the rats randomized to Chain II Group, when Phase 1 was initiated, the duration of the light was initially the same of the delay, but was reduced gradually across phase until it was no longer present with the delay period. For rats randomized to Chain III Group, there was no delay signal initially, but its duration was increased across phase until it equalized the duration of the programmed delay (4 s). The duration of the delay signal was always the same of the delay for the rats employed on Chain I Group, while the was no delay signal for rats randomized to Tand Group. With the rats randomized to the Control Group there was no delay on reinforcement. Within subjects, response rates where higher as the duration of the delay signal increased, with the highest acceleration when its duration was minimal. Response rates where higher also to prior rates when the duration of the delay signal was reduced, with the highest acceleration when its duration was minimal. The findings are discussed in terms of the conditioned reinforcement of the delay signal by reduction the delay between its onset and the reinforcer / Quinze ratos foram distribuídos em cinco grupos com o objetivo de avaliar os efeitos de diferentes durações de luz, que eram apresentadas durante o período de atraso, sobre a aquisição e manutenção da resposta de pressão à barra com atraso de reforço, sem modelagem dessa resposta. O estudo foi dividido em duas fases com dezessete sessões cada (quinze sessões experimentais e duas em extinção). Na Fase 1, para os sujeitos do Grupo Encadeado III, a luz não estava presente nas sessões iniciais. Com o decorrer das sessões, a duração da luz foi aumentada gradualmente até que a sua duração cobrisse todo o período de atraso. Para os sujeitos do Grupo Encadeado II, duração da luz equivalia à totalidade do período de atraso nas sessões iniciais, sendo reduzida gradualmente a sua duração ao longo das sessões até não haver luz durante o período. Nas sessões dos sujeitos do Grupo Tandem não havia luz durante o período de atraso, enquanto nas sessões dos sujeitos do Grupo Encadeado I a duração luz sempre cobria a totalidade do período. Já nas sessões dos sujeitos do Grupo Controle não havia atraso de reforço. Decorrida a Fase 1, o período de atraso foi aumentado de 4 s para 8 s e iniciou-se a Fase 2, idêntica à anterior. Foi observada, em ambas as fases, um aumento na taxa de emissões e de reforços produzidos pelos sujeitos do Grupo Encadeado III na medida que a duração da luz era aumentada, com um aumento maior em ambas as fases quando a luz tinha sua duração mínima. Do mesmo modo, foi notado um pequeno aumento na taxa de emissões e de reforços produzidos pelos sujeitos do Grupo Encadeado II a partir da redução na duração da luz, com aumento maior quando a duração da luz era mínima. Os resultados do presente estudo foram discutidos a partir da noção de reforçador condicionado e da hipótese da redução do atraso proposta por Fantino (1969, 1977)