Made available in DSpace on 2015-05-14T12:56:00Z (GMT). No. of bitstreams: 1 Arquivototal.pdf: 2176646 bytes, checksum: 1bc824e5cb69d2fcdee753f80f5eb8df (MD5) Previous issue date: 2012-03-13 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The aim of this study was to verify the applicability of parameters for human identification using the frontal sinuses, used by Tatlisumak et al. (2007), using axial and coronal reconstructions of CBCT and extraoral radiographs. From 58 dry disjointed skulls existing in the Management of Legal Medicine of Paraiba (PB-GEMOL) and University Center of Joao Pessoa, UNIPÊ, 26 skulls were selected. The acquisition of anteroposterior radiographs of the skull and lateral view were obtained through X-ray machine pan Rotograph Plus ® (Dabi Atlante Ltda., Ribeirão Preto, São Paulo, Brazil) and the CT at New iCAT device Generation ® (Imaging Sciences International, Pennsylvania, USA), adopting a specific methodology in order to standardize the tests to obtain and ensure the reproducibility of the study. The images were evaluated by two examiners calibrated in darkened environment and in two different times, with a minimum interval of one week. Assessments of axial and coronal reconstructions were performed with the aid of a 23 "program and iCat Vision (Imaging Sciences International, Pennsylvania, USA). For evaluation of extraoral radiographs were traced on paper made using ultrafan of 600 lux light box with mask and measurements with the aid of a high precision digital caliper Mitutoyo series 167 (Mitutoyo, Suzano, Brazil). Categorical variables were discrete and analyzed using the kappa test and continuous variables by Correlation Coefficient of Concordance Lin. Methods of analysis by cone beam CT and radiographic were mostly consistent, with only a few variables with unsatisfactory results (capd, and dpele dpontalt). For categorical variables and discrete intra-and inter-was great-perfect for both methods, as continuous variables showed moderate to excellent results. It is concluded that: the methodology proposed in this paper, using the parameters of the job Tatlisumak et al. (2007), are applicable and reliable in extraoral radiographs (X-rays AP and lateral radiographs of the skull face) and axial and coronal reconstructions of CBCT for human identification by frontal sinus, intra-and inter the parameters used by Tatlisumak et al. (2007) with CBCT imaging modality varies from substantial to excellent, and moderate to excellent radiographic images, there is a greater power of reproducibility and accuracy of the proposed method using the axial and coronal reconstructions of CBCT taking extraoral radiographs also reliability , the least consistent variable in the analysis by the images of CBCT is a measure capd (poor agreement), while the radiographic images and are dpele dpontalt (bad matches). This result indicates that these parameters are more susceptible to errors by evaluators, since it needs to use multiple points of reference for their measurements. / O objetivo neste estudo foi verificar a aplicabilidade de parâmetros de identificação humana por meio dos seios frontais, utilizados por Tatlisumak et al. (2007), com auxílio das reconstruções axiais e coronais de tomografia computadorizada de feixe cônico (TCFC) e radiografias extrabucais. De um universo de 58 crânios secos desarticulados existentes na Gerência Executiva de Medicina e Odontologia Legal da Paraíba (GEMOL-PB) e Centro Universitário de João Pessoa, Unipê, foram selecionados 26 crânios. As aquisições das imagens radiográficas póstero-anterior de crânio e lateral de face, foram obtidas por meio do aparelho de raios X panorâmico Rotograph Plus® (Dabi Atlante Ltda., Riberão Preto, São Paulo, Brasil) e as tomográficas, pelo aparelho iCAT New Generation® (Imaging Sciences International, Pennsylvania, EUA), adotando-se uma metodologia específica como forma de padronizar a obtenção dos exames e garantir a reprodutibilidade do estudo. As imagens foram avaliadas por dois examinadores previamente calibrados, em ambiente escurecido e em dois tempos distintos, com um intervalo mínimo de uma semana. As avaliações das reconstruções axiais e coronais foram realizadas com o auxílio de um monitor de 23 e programa iCat Vision (Imaging Sciences International, Pennsylvania, EUA). Para avaliação das imagens radiográficas extrabucais, foram realizados traçados em papel ultrafan utilizando negatoscópio de 600 lux com máscara e as mensurações com auxílio de um paquímetro digital de alta precisão Mitutoyo série 167 (Mitutoyo Sul Americana, Suzano, Brasil). As variáveis categóricas e discretas foram analisadas por meio do teste kappa e as variáveis contínuas pelo Coeficiente de Correlação de Concordância de Lin. Os métodos de análise pelas tomografias de feixe cônico e radiográficas foram em sua maioria concordantes, apresentando apenas algumas variáveis com resultados insatisfatórios (capd, dpele e dpontalt). Para as variáveis categóricas e discretas houve concordância intra e interexaminadores de ótima a perfeita em ambos os métodos, já as variáveis contínuas apresentaram resultados de moderada a excelente. Conclui-se que: a metodologia proposta no presente trabalho, utilizando os parâmetros do trabalho de Tatlisumak et al. (2007), são aplicáveis e confiáveis em radiografias extrabucais (radiografias PA de crânio e radiografias laterais de face) e reconstruções axiais e coronais de TCFC para a identificação humana pelos seios frontais; a concordância intra e interexaminador nos parâmetros utilizados por Tatlisumak et al. (2007) com a modalidade de imagem TCFC varia de boa a excelente; e de moderada a excelente nas imagens radiográficas; há um maior poder de reprodutibilidade e precisão do método proposto utilizando as reconstruções axiais e coronais de TCFC, tendo as radiografias extrabucais também confiabilidade; a variável menos concordante na análise pelas imagens de TCFC é a medida capd (concordância ruim); já pelas imagens radiográficas são dpele e dpontalt (concordâncias ruins). Tal resultado indica que estes parâmetros são mais passíveis de erros por parte dos avaliadores, uma vez que deve-se utilizar vários pontos de referência para suas mensurações.

The objective of this work is to identify the factors that favors the movement of frontal systems over South America (SA) and their influences in the state of Alagoas (AL), Brazil and determine the synoptic patterns characteristic of the penetration events of fronts into the Tropics, besides testing new diagnostic tools to describe these systems and others. Twenty six frontal systems that direct or indirectly influenced the weather conditions over AL for the 2004 2006 period were analyzed. The cases were sorted out in four groups (G) according to the similar characteristics among the events. They were: G1 passage of the frontal system or its extremity over AL; G2 cloud band over AL, organized by the frontal tip over the Southern Tropical Atlantic (STA); G3 convective activity over AL, due to the frontal tip over STA and G4 passage of the frontal system or its tip over STA at the same latitude of the AL coast. The fronts were identified using different methods: classical, satellite imagery, equivalent potential temperature (θe) fields and advection of equivalent potential temperature (Aθe). The global model NCEP/NCAR Reanalysis data and infra-red images were used. In general, the fronts that reach AL are not associated with friagem events. The G1 events were found in all seasons of the year. The G2 cases were concentrated during Southern Hemisphere (SH) winter and onset of the transition to warmer months. The G3 events occur during the end of the transition to warmer months, SH summer and onset of the transition to colder months. No event fell in G4. The superposition of several factors is important to characterize the frontal influences in AL: frontal regeneration ahead of the main front, development of secondary fronts and possible instantaneous occlusion, interaction of the analyzed frontal with other frontal waves, interaction of the frontal tip with cyclonic perturbations over the continent (of baraclinic nature during winter months and of barotropic nature during summer months) and jet stream positioned to the north of its climatological position. The fronts responsible for convecdtive activity over AL, from November to March, are associated with the interaction of the Southern America Convergence Zone and one Upper Air Cyclonic Vortex. The presence of warm cored barotropic high pressure over SA inhibits the development of the frontal tip over the Brazilian coast during the winter months. The coupling between the upper air wave train of synoptic scale (identified by the meridional flux linking the exit of Polar Jet Stream to the entrance of the Subtropical Jet Stream) allows the merging of different frontal waves in low levels and the incursion of cold air equatorward, being responsible for the frontal regeneration and the formation of new cyclones in the family. The θe and Aθe fields are sufficient for the analyses and identification of the frontal systems, and should be part of an operational weather forecast suite. Based on these fields a conceptual model for the development of baroclinic cyclone in the Tropics is presented. / Fundação de Amparo a Pesquisa do Estado de Alagoas / Este trabalho teve o objetivo de identificar os fatores que favorecem o deslocamento dos sistemas frontais sobre a América do Sul (AS) e suas influências sobre o Estado de Alagoas (AL). Procurou-se encontrar padrões sinóticos que expliquem os mecanismos e processos atmosféricos que comandam o deslocamento das frentes para regiões tropicais, além de testar novas ferramentas que possibilitem a melhor identificação dos sistemas envolvidos nesses processos. Assim, foi feita a analise de 26 sistemas frontais que influenciaram direta ou indiretamente as condições de tempo sobre o Estado de AL, para três anos (2004 a 2006). Os casos foram divididos em 4 grupos (G), de acordo com as características similares encontradas entre os eventos. G1 - passagem do sistema frontal, ou de sua extremidade, sobre o estado de AL; G2 - banda de nebulosidade sobre o Estado de AL, organizada pela extremidade frontal sobre o Atlântico Tropical Sul (ATS); G3 atividades convectivas sobre o Estado de AL, organizadas pela extremidade frontal sobre o ATS e G4 - passagem do sistema frontal, ou de sua extremidade, sobre o ATS, na mesma latitude da costa alagoana. As frentes foram identificadas por diversos métodos: sinótico clássico, dados de satélite e campos horizontais de temperatura potencial equivalente (θe) e advecção de temperatura potencial equivalente (Aθe). Foram utilizados dados de reanálise do modelo global NCEP/NCAR e imagens de satélite no canal infravermelho. Em geral, as frentes que chegaram até AL não estiveram associadas a eventos de friagem . Os eventos do G1foram encontrados em todas as estações do ano. Os casos do G2 se concentraram durante as estações de inverno austral e inicio da transição quente. Os eventos do G3 tenderam a ocorrer durante o fim da transição quente, verão austral e início da transição fria. Não houve eventos que satisfizessem as condições do G4. A sobreposição de vários fatores se torna importantes para as influências frontais em AL: regenerações frontais, novas ciclogêneses na frente principal, surgimento de frentes secundárias e possíveis oclusões instantâneas, interação da onda frontal analisada com outras ondas frontais, interação da extremidade frontal com perturbações ciclônicas sobre o continente (baroclínica nos meses de inverno e barotropica no verão) e corrente de jato posicionada ao norte da sua climatologia. De novembro a março, as frentes que organizaram atividades convectivas sobre AL estiveram associadas à interação da ZCAS e VCAN s. A atuação de uma Alta Barotrópica de Núcleo Quente sobre a AS oferece restrição para o desenvolvimento da extremidade frontal na costa do Brasil, durante os meses de inverno. O acoplamento entre os trens de onda de escala sinótica em altos níveis, identificado por um fluxo meridional que conecta a saída da Corrente de Jato Polar com a entrada da Corrente de Jato Subtropical, permite a fusão de ondas frontais distintas em baixos níveis e a incursão de ar frio em direção ao equador, podendo provocar a regeneração das frentes e a formação de novos ciclones na família. Os campos de θe e Aθe são eficientes para analise e identificação de sistemas frontais, devendo ser incorporados a previsão operacional do tempo. Com base nesses campos, foi proposto o modelo conceitual de desenvolvimento do ciclone baroclínico na região tropical.

A unicidade da cavidade sinusal frontal é um importante fator para a identidade humana. O uso de registros de imagens dessa cavidade para a identificação forense é amplamente difundido, sendo uma metodologia secundária segundo a INTERPOL. Recentes avanços nas tecnologias de imagem permitiram o registro de imagens tridimensionais dessa cavidade. Nosso objetivo foi validar a metodologia proposta por Beaini et al. (2015), padronizando critérios para a obtenção de imagens tridimensionais da cavidade sinusal frontal com tomografia computadorizada de feixe cônico e avaliando a capacidade desses dados para a identificação humana. Para tanto, utilizamos um banco de imagens tomográficas de 200 pacientes randomizados e analisados por três observadores. As imagens foram exportadas em formato DICOM e submetidas a dois processos de segmentação distintos e sobreposição tridimensional. Realizou-se a metodologia descrita para estabelecer a identificação entre pacientes randomizados. Os resultados mostraram que há uma diferença significativa entre os processos de segmentação, sendo mais indicada a técnica de segmentação manual. A metodologia proposta por Beaini et al. (2015) foi validada e um total de 166 pacientes foram identificados. O volume da cavidade sinusal possui um elevado potencial de identificação com uma probabilidade aproximada de 85% para determinar o gênero dos indivíduos. / The uniqueness of the frontal sinus cavity is an important factor for establishing human identity. The usage of imaging records of this cavity for human identity is a secondary methodology according to the INTERPOL protocols. Recent advances in imaging technologies have enabled the three-dimensional imaging records of this cavity. Our goal was to validate the methodology proposed by Beaini et al. (2015), by developing standardized criteria for the use of cone beam computed tomography three-dimensional images of the front sinus and evaluating the ability of these data for human identification. The aim of this study was to investigate a total of 200 imaging records from randomized patients that were analyzed by three observers. Images were exported in DICOM format and underwent two distinct segmentation processes and a three-dimensional overlap. The Beaini et al. (2015) technique was applied to establish identification of the randomized patients. My results showed a significant difference between both segmentation processes, with manual segmentation showing the best results. Beaini et al. (2015) technique was validated and a total of 166 patients were identified. The volume of the sinus cavity has a high identification probability with a rough probability of 85% to determine the sex of individuals.

As teorias mais influentes acerca do funcionamento do córtex pré-frontal (PFC) tomam essa estrutura como um córtex de associação e de integração de informações oriundas de outras estruturas nervosas. Isso implicaria na participação direta do PFC nos processos de memória operacional e em processo atencionais. Estudos hodológicos e neurofisiológicos sugerem, que o córtex orbitofrontal (OFC) seria responsável pela integração de informações de caráter sensorial, motivacional e afetivo, enquanto o córtex pré-frontal ventromedial (vmPFC) seria diretamente ligado ao OFC, tendo um papel crucial na codificação de estímulos emocionais oriundos da amígdala. Nesse contexto, é aceito que a integração das informações feita por essas estruturas seja essencial para o processo de tomada de decisões, uma vez que esse comportamento necessita de uma avaliação do ambiente em termos de comparações de situações novas a experiências prévias armazenadas na memória, assim como um balanço entre custos, benefícios e cálculo de possíveis valores da recompensa. Para testar essas hipóteses, ratos com danos seletivos no vmPFC foram submetidos testes de avaliação de ansiedade e medo condicionado no paradigma de teste e reteste no labirinto em cruz elevado (LCE), assim como a testes de memória de referência espacial e memória operacional no labirinto aquático de Morris. Outro grupo de animais teve matrizes de multi-eletrodos implantadas no OFC para a avaliação da atividade neuronal dessa estrutura em um teste envolvendo tomada de decisões, no qual devem escolher entre ganhar 1 pellet de chocolate imediatamente ou 4 pellets envolvendo atrasos variados. No teste no LCE, animais com lesão no vmPFC diferem dos animais controle por apresentarem uma diminuição do tempo de avaliação de risco sem apresentar alterações nos parâmetros que aferem memória, atividade locomotora e ansiedade. No teste de memória de referência espacial após treinamento extensivo de busca pela plataforma em um mesmo local no labirinto aquático, animais com lesão persistem no local quando se retira a plataforma (probe test). Já no teste de memória operacional, no qual a localização da plataforma é alterada diariamente, esses animais não diferem do grupo controle. Na tarefa envolvendo tomada de decisões, observou-se uma atividade eletrofisiológica de neurônios do OFC relacionada ao momento crítico no qual o animal deve realizar uma escolha. Em conjunto, esses resultados mostram que o vmPFC está relacionado à flexibilidade comportamental e tomada de decisões, possivelmente em conjunto com o OFC, cuja atividade neuronal sugere uma participação nos processos de tomada de decisões e de elaboração de estratégias / The most influential theories on the function of the prefrontal cortex (PFC) suggest that this structure is an association cortex, responsible for integration of information received from other parts of the brain. This would implicate in direct participation of the PFC in working memory and attentional processes. Given this context, hodological and neurophysiological studies suggest that the orbitofrontal cortex (OFC) would be responsible for the integration of sensory, motivational and affective aspects, while the ventromedial prefrontal cortex (vmPFC), which is directly connected to the OFC, would have a key role in encoding emotional stimuli from the amygdala. It is well accepted that the processing of these aspects of information is crucial for decision-making processes, given the fact that this expression of behavior requires an evaluation of the environment in terms of comparing novel situation to previous experiences, as well as processing the balance between costs, outcomes and reward values. In order to test these hypotheses, rats with selective lesions to the vmPFC were subjected to the elevated plus maze (EPM) to evaluate anxiety and conditioned fear in the test retest paradigm. Animal were also tested in a spatial reference memory and a working memory tasks in the Morris water maze. Another group of rats had multi-electrode arrays chronically implanted in the OFC for the evaluation of the neuronal activity during a decision-making task, in which the animals had to choose between a small reward of one chocolate pellet immediately and a large reward of four chocolate pellets after varying delays. The results of the EPM show that animals with lesion to the vmPFC differ from control animals by showing diminished time evaluating risk in the second exposure to the EPM, without damage to locomotor activity, memory and anxiety levels. In the reference spatial memory task in the water maze, after extensive training searching for the hidden platform in the same location, lesioned animals persisted searching for the platform in that particular location after it was removed (probe test). However, in the working memory task, in which the platform is presented in a different location each day, lesioned animals did not differ from control animals. In the decision-making task, differential electrophysiological activity in OFC neurons was observed, particularly in the moment of the task in which the animal was required to perform the choice between rewards. Together, these results suggest that the vmPFC is related to behavioral flexibility and decision-making, possibly acting together with the OFC, which neuronal activity suggests participation in decision-making processes

O córtex pré-frontal medial (PFCm) é caracterizado por entradas glutamatérgicas e dopaminérgicas que convergem sobre os mesmos neurônios alvos. Devido à escassa informação sobre as bases anatômicas das interações entre a dopamina (DA) e o glutamato (Glu), mapeamos a distribuição de subunidades (Su) de receptores (Rs) de Glu do tipo AMPA, NMDA e kainato no PFCm e investigamos a sua expressão em neurônios contendo a fosfoproteína DARPP-32 e em interneurônios. Os resultados mostram que as Su GluR2/3 dos Rs do tipo AMPA são as mais amplamente distribuídas no PFCm e expressas em todos os neurônios DARPP-32+. GluR2/3 é também amplamente co-localizado com as Su NMDAR1 dos Rs de Glu do tipo NMDA e GluR5/6/7 dos Rs do tipo kainato. Em contraste, as Su GluR1 e GluR4 são somente fracamente expressos no PFCm e não são co-localizados com DARPP-32, porém com GABA ou parvalbumina. Os resultados indicam que as Su GluR2/3, NMDAR1 e GluR5/6/7 são amplamente expressos em neurônios piramidais DARPP-32+ enquanto GluR1 e GluR4 são predominantemente expressos em interneurônios do PFCm. / The medial prefrontal cortex (PFCm) is characterized by glutamatergic and dopaminergic afferents that converge on the same target neurons. Since there is only limited information about the anatomical bases for interactions between dopamine (DA) and glutamate (Glu), we mapped the distribution of AMPA, NMDA and kainate Glu receptor (Rs) subunits (Su) in the PFcm and investigated their expression in neurons containing the phosphprotein DARPP-32 and in interneurons. Results show that the Su GluR2/3 of AMPA type Rs are the most prominently distributed in the PFCm and expressed in all neurons DARPP-32+. GluR2/3 is also widely co-localized with the NMDA type Su NMDAR1 and the Kainate Su GluR5/6/7. In contrast, the Su GluR1 and GluR4 are only weakly expressed in the PFCm and are not colocalized with DARPP-32 but with GABA or parvalbumin. Results indicate that the Su GluR2/3, NMDAR1, and GluR5/6/7 are prominently expressed in DARPP-32+ pyramidal neurons, whereas GluR1 and GluR4 are predominantly expressed by interneurons in the PFC.

Cette thèse s’inscrit dans le cadre des travaux menés par PSA Peugeot Citroën pour l’allègement de ses véhicules. Les optimisations masse multi-prestations réalisées sur le périmètre de la structure contribuent directement à cette démarche en recherchant une allocation d’épaisseurs de tôles à masse minimale qui respectent des spécifications physiques relatives à différentes prestations (choc, vibro-acoustique, etc.). Ces spécifications sont généralement évaluées à travers des modèles numériques à très haute-fidélité qui présentent des temps de restitution particulièrement élevés. Le recours à des fonctions de substitution, connues sous le nom de métamodèles, reste alors la seule alternative pour mener une étude d’optimisation tout en respectant les délais projet. Cependant la prestation qui nous intéresse, à savoir le choc frontal, présente quelques particularités (grande dimensionnalité, fortes non-linéarités, dispersions physique et numérique) qui rendent sa métamodélisation difficile.L’objectif de la thèse est alors de proposer une approche d’optimisation basée sur des métamodèles adaptatifs afin de dégager de nouveaux gains de masse. Cela passe par la prise en compte du choc frontal dont le caractère chaotique est exacerbé par la présence d’incertitudes. Nous proposons ainsi une méthode d’optimisation fiabiliste avec l’introduction de quantiles comme mesure de conservatisme. L’approche est basée sur des modèles de krigeage avec enrichissement adaptatif afin de réduire au mieux le nombre d’appels aux modèles éléments finis. Une application sur un véhicule complet permet de valider la méthode. / One of the most challenging tasks in modern engineering is that of keeping the cost of manufactured goods small. With the advent of computational design, prototyping for instance, a major source of expenses, is reduced to its bare essentials. In fact, through the use of high-fidelity models, engineers can predict the behaviors of the systems they design quite faithfully. To be fully realistic, such models must embed uncertainties that may affect the physical properties or operating conditions of the system. This PhD thesis deals with the constrained optimization of structures under uncertainties in the context of automotive design. The constraints are assessed through expensive finite element models. For practical purposes, such models are conveniently substituted by so-called surrogate models which stand as cheap and easy-to-evaluate proxies. In this PhD thesis, Gaussian process modeling and support vector machines are considered. Upon reviewing state-of-the-art techniques for optimization under uncertainties, we propose a novel formulation for reliability-based design optimization which relies on quantiles. The formal equivalence of this formulation with the traditional ones is proved. This approach is then coupled to surrogate modeling. Kriging is considered thanks to its built-in error estimate which makes it convenient to adaptive sampling strategies. Such an approach allows us to reduce the computational budget by running the true model only in regions that are of interest to optimization. We therefore propose a two-stage enrichment scheme. The first stage is aimed at globally reducing the Kriging epistemic uncertainty in the vicinity of the limit-state surface. The second one is performed within iterations of optimization so as to locally improve the quantile accuracy. The efficiency of this approach is demonstrated through comparison with benchmark results. An industrial application featuring a car under frontal impact is considered. The crash behavior of a car is indeed particularly affected by uncertainties. The proposed approach therefore allows us to find a reliable solution within a reduced number of calls to the true finite element model. For the extreme case where uncertainties trigger various crash scenarios of the car, it is proposed to rely on support vector machines for classification so as to predict the possible scenarios before metamodeling each of them separately.

La capacité à évaluer les résultats nos actions est fondamentale pour adapter et optimiser notre comportement et dépend d’un système superviseur chargé d’évaluer l’action, détecter les erreurs, déclencher des corrections.Le réseau neuronal sous-jacent la supervision de l’action n’a pas été complètement caractérisé chez l’homme.Dans une première étude nous avons enregistré dans l’Aire Motrice Supplémentaire (AMS) des LFP évoqués par les réponses et modulés par la performance. Des LFP évoqués exclusivement par les erreurs ont été enregistrés plus tardivement dans le cortex préfrontal médian.Dans la deuxième étude, nous avons observé que les activités de hautes-fréquences gamma sont, elles aussi, modulées par la performance des sujets, mais dans un vaste réseau frontal et extra-frontal.Dans une troisième étude, utilisant des enregistrements simultanés électroencéphalographiques (EEG) et magnétoencéphalographiques (MEG), nous observé une activité évoquée par un feedback interne sur l’EEG (mais pas en MEG), alors qu'une activité évoquée par le feedback externe était bien visible sur les enregistrements MEG, indiquant que les générateurs de ces deux activités cérébrales, sont différents. Nos résultats montrent une implication de l’AMSp dans la supervision de l’action chez l’homme, bien plus importante que ce que l’on soupçonnait auparavant. L’AMS évalue précocement, et de façon continue, l’action en cours et elle engage vraisemblablement des structures préfrontales en cas d’erreur seulement. Le traitement de l’erreur d’action, selon qu'il se fonde sur des informations internes ou externes est certainement sous-tendu par des réseaux corticaux différents. / The capacity to evaluate the outcome of our actions is fundamental for adapting and optimizing behaviour. This capability depends on an action monitoring system in charge of assessing ongoing actions, detecting errors, and evaluating outcomes.Electrical brain activity evoked by negative outcomes is thought to originate within the medial part of the frontal cortex. Nonetheless, the underlying neuronal network is incompletely characterised in humans.In the two first studies, we investigated the anatomical substrates of action monitoring in humans using intracerebral local field potential (LFP) recordings of cerebral cortex from epileptic patients. Response evoked LFPs sensitive to outcome were recorded from the Supplementary Motor Area proper (SMA), while LFPs evoked exclusively by errors were recorded later in the medial prefrontal cortex. High-gamma-frequency activity (60-180 Hz) was modulated as a function of action outcome in a vast frontal and extra-frontal network.In a third study using simultaneous recording of electroencephalography (EEG) and magnetoencephalography (MEG), we found that error related activity was detected by EEG (but not by MEG), while feedback-related activity was detected by MEG, indicating that the sources of these two forms of outcome-modulated brain activity are different.To conclude the SMA is much more involved in action monitoring than previously thought. SMA rapidly and continuously assesses ongoing actions and likely engages more rostral prefrontal structures in the case of error. Processing of action errors and of negative externally delivered feedback therefore appears to be supported by distinct cortical networks.

L’attention visuelle est un phénomène primordial pour la perception visuelle de notre environnement. Elle correspond à l’ensemble des mécanismes qui permettent la sélection d’information visuelle dans le but de la traiter en particulier. Lorsque volontaire, son orientation est considérée comme lente, contrairement à l’orientation de l’attention visuelle involontaire, qui est rapide et réflexive. Grâce à une étude de psychophysique humaine, nous montrons que le déplacement volontaire de l’attention est rapide mais qu’un ensemble de processus cognitifs ont jusqu’à présent masquer ce phénomène.Au niveau cérébral, l’orientation de l’attention visuelle est sous tendue par un réseau d’aires,impliquant le champ oculomoteur frontal (FEF) et l’aire latérale intrapariétale (LIP). En enregistrant l’activité unitaire des neurones de ces 2 aires de 2 macaques Rhésus impliqués dans une tâche de détection de cible nécessitant l’orientation volontaire de l’attention visuelle,nous montrons que ces 2 aires jouent un rôle différent. Ainsi FEF semble impliqué dans l’orientation des capacités attentionnellles et représente également la sélection de l’objet important. LIP n’est pas impliqué dans l’orientation de l’attention visuelle, en revanche, ses neurones présentent une réponse cognitive spécifique de la détection de la cible. Nos résultats suggèrent que FEF contrôle l’orientation volontaire de l’attention visuelle alors que LIP sert à la détection de la cible.Qui plus est, nous montrons l’existence dans FEF d’une nouvelle classe de cellules impliqués dans le contrôle exécutif des fonctions cognitives et notamment attentionnelles / Visual attention is a critical process to a correct perception of our visual environment.This term includes all mechanisms involved in the selection of information in order to processit in priority. It is generally proposed that voluntary orientation of attentional capacity is a220slow and sustained process, while unvoluntary orientation is fast. We show here by apsychophysical study that voluntary orientation is in fact a rapid process that is easely maskedby others cognitiv process of general engagement.This phenomenon is sustained by a large network of cerebral areas, including the Frontal Eye Field (FEF), and the Lateral IntraParietal area (LIP). We recorded neuronal activity of 2monkey’s FEF and LIP neuronal activity while they were engaged in a attentional task. Weshow here that these 2 areas play 2 crucial differents roles. Contrary to FEF, that is highlyinvolved in attentional orientation and engagement, LIP neuronal activity present few attentional modulations. LIP and FEF cells present large cognitive activities selectives to selection of the important event of the task. We hypothesis that FEF controles the voluntary orientation of visual attention while LIP detects the target.More over, we highly the existence of a new FEF’s cell category involved in the executive control of cognitives function (as attentional).

L'objectif de cette thèse a été d'investiguer la question de la généralité et de l'automatisation des processus de contrôle inhibiteur au fil du développement cognitif. Cette question a été approchée par différentes études expérimentales menées chez l'enfant, chez l'adolescent et chez l'adulte. Trois études ont porté sur la généralité des processus de contrôle inhibiteur agissant dans des tâches appartenant à des domaines cognitifs différents. Dans la première, nous avons voulu répondre à deux problématiques liées aux divergences présentes dans la littérature sur le développement du contrôle inhibiteur dans des contextes émotionnels. Le but de cette étude était de déterminer (a) si le contrôle inhibiteur froid (dans des contextes affectivement neutres) et le contrôle inhibiteur chaud (dans des contextes émotionnellement chargés) suivent un pattern développemental identique, particulièrement à l'adolescence et (b) le degré de spécificité de ces deux types de contrôle inhibiteur au fil du développement. Pour cela, nous avons comparé les performances d'enfants de 10 ans, d'adolescents de 13 ans et de jeunes adultes de 21 ans à une tâche de Stroop couleur-mot affectivement neutre et une tâche de Stroop émotionnel. Dans une deuxième étude, nous avons testé auprès d'un groupe d'enfants de 9 ans si les processus inhibiteurs impliqués dans une tâche classique piagétienne de conservation du nombre (i.e., domaine logico-mathématique) étaient identiques ou partiellement identiques à ceux impliqués dans la résolution de la tâche neuropsychologique classique de Stroop couleur-mot (i.e., domaine verbal). Dans une troisième étude, nous avons testé auprès d'un groupe d'enfants de 10 ans et d'un groupe de jeunes adultes de 20 ans la transférabilité des processus inhibiteurs entre une tâche de discrimination de lettres en miroir (dont il a récemment été démontré qu'elle nécessite l'inhibition) et une tâche classique de Stroop couleur-mot, afin de déterminer (a) si la mise en place de mécanismes inhibiteurs impliqués dans la résolution d'un conflit à un niveau perceptif très précoce (la reconnaissance visuelle de symboles) peut faciliter la résolution d'un conflit à un niveau de traitement beaucoup plus tardif (niveau sémantique et moteur), et (b) si l'âge affecte cette transférabilité. Ensuite nous nous sommes intéressés à l'automaticité des processus de contrôle inhibiteur, testant si le contrôle inhibiteur peut fonctionner de manière totalement inconsciente sur des conflits provoqués par deux stimuli subliminaux interférents. Pour cela, nous avons conçu un paradigme d'amorçage composé d'essais dans lesquels un item de Stroop inversé subliminal précédait un item de Stroop visible. Le but de ce paradigme était de vérifier la présence d'un effet d'adaptation de conflit et d'un effet d'amorçage négatif du stimulus subliminal sur le stimulus visible, deux effets rapportés dans les études utilisant des stimuli visibles et suggérant un transfert des processus de contrôle de l'amorce à la cible. Enfin dans une cinquième étude nous avons cherché à savoir si les différences interindividuelles en termes de contrôle inhibiteur découlent en partie des processus prénataux, sur base de l'analyse de la forme sulcale du cortex, considérée comme une caractéristique qualitative de l'anatomie cérébrale déterminée pendant la vie fœtale et stable au cours du développement. En utilisant l'imagerie par résonance magnétique anatomique, nous avons analysé les corrélations entre les performances à une tâche de Stroop couleur-mot et la forme sulcale de deux régions clefs du réseau neuronal du contrôle inhibiteur, le cortex cingulaire antérieur dorsal et le sillon frontal inférieur (qui limite le gyrus frontal inférieur), chez un groupe d'enfants de 10 ans et un groupe d'adultes de 22 ans. En conclusion, cette thèse apporte un nouvel éclairage à la question de la généralité et de l'automatisation des processus d'inhibition exécutive dans une perspective développementale / The objective of this thesis was to investigate the question of the domain-generality of inhibitory control and its automatization throughout development. This question has been approached by various experimental studies in children, adolescents and adults. Three studies have focused on the generality of control processes operating in tasks belonging to different cognitive domains. In the first study, we wanted to answer two questions related to the discrepancies found in the literature on the development of inhibitory control in affectively charged contexts. The aim of this study was to determine (a) whether cool inhibition (control processes in emotionally neutral contexts) and hot inhibition (control processes in emotionally charged contexts) follow the same developmental pattern, and (b) the degree of specificity of these two types of inhibitory control throughout development. We thus compared the performance of 10-year-olds, 13-year-olds and 21-year-olds to an emotionally neutral color-word Stroop task and an emotional Stroop task. In a second study on 9-year-old children, we tested whether the inhibitory processes involved in a classical Piagetian conservation task (i.e., logico-mathematical domain) were identical or partially identical to those involved in the resolution of the classical neuropsychological color-word Stroop task (i.e., verbal domain). In a third study, we tested on a group of 10-year-old children and a group of 20-year-old young adults the transferability of inhibitory processes between a mirror letters discrimination task (that has recently been shown to require inhibition) and a color-word Stroop task, to determine (a) whether the resolution of a conflict at an early perceptual stage of the processing stream (recognition of visual symbols) can facilitate the resolution of a conflict arising at a much later stage (semantic and motor levels), and (b) if age affects this transferability. Then we looked at the automaticity of the inhibition processes by testing whether inhibitory control can operate completely unconsciously on conflicts arising between two subliminal interfering stimuli. To this end, we designed a priming paradigm consisting of trials in which a subliminal reverse Stroop item preceded a visible Stroop item. The aim of this paradigm was to verify the presence of a conflict adaptation effect and a negative priming effect produced by the subliminal items on the visible items. These two effects are commonly reported in studies using visible stimuli and suggest a transfer of control processes from the prime to the probe. Finally, in a fifth study, we investigated whether inter-individual differences in inhibitory control are in part due to prenatal processes, based on the analysis of the sulcal pattern, considered as a qualitative feature of the cerebral anatomy that is determined during fetal life and is stable during development. Using anatomical magnetic resonance imaging, we analyzed the correlations between the performance on a color-word Stroop task and the sulcal pattern of two key regions of the inhibitory control neural network, the dorsal anterior cingulate cortex and the inferior frontal sulcus (which limits the lower frontal gyrus) in a group of 10-year-old children and in a group of 22-year-old adults. In conclusion, this thesis sheds new light on the question of the generality and the automatization of the inhibitory control processes from a developmental perspective.

Schizophrenia remains an enigmatic disorder with unclear neuropathology. Recent advances in neuroimaging and genetic research suggest alterations in glutamate-dopamine interactions adversely affecting synaptic plasticity both intracortically and subcortically. Relating these changes to the manifestation of symptoms presents a great challenge, requiring a constrained framework to capture the most salient elements. Here, a biologically-grounded computational model of basal ganglia-mediated action selection was used to explore two pathological processes that hypothetically underpin schizophrenia. These were a drop in the efficiency of cortical transmission, reducing both the signal-to-noise ratio (SNR) and overall activity levels; and an excessive compensatory upregulation of subcortical dopamine release. It was proposed that reduced cortical efficiency was the primary process, which led to a secondary disinhibition of subcortical dopamine release within the striatum. This compensation was believed to partly recover lost function, but could then induce disorganised-type symptoms - summarised as selection ”Instability” - if it became too pronounced. This overcompensation was argued to be countered by antipsychotic medication. The model’s validity was tested during an fMRI (functional magnetic resonance imaging) study of 16 healthy volunteers, using a novel perceptual decision-making task, and was found to provide a good account for pallidal activation. Its account for striatum was developed and improved with a small number of principled model modifications: the inclusion of fast spiking interneurons within striatum, and their inhibition by the basal ganglia’s key regulatory nucleus, external globus pallidus. A key final addition was the explicit modelling of dopaminergic midbrain, which is dynamically regulated by both cortex and the basal ganglia. This enabled hypotheses concerning the effects of cortical inefficiency, compensatory dopamine release and medication to be directly tested. The new model was verified with a second set of 12 healthy controls. Its pathological predictions were compared to data from 12 patients with schizophrenia. Model simulations suggested that Instability went hand-in-hand with cortical inefficiency and secondary dopamine upregulation. Patients with high Instability scores showed a loss of SNR within decision-related cortex (consistent with cortical inefficiency); an exaggerated response to task demands within substantia nigra (consistent with dopaminergic upregulation); and had an improved fit to simulated data derived from increasingly cortically-inefficient models. Simulations representing the healthy state provided a good account for patients’ motor putamen, but only cortically-inefficient simulations representing the ill state provided a fit for ventral-anterior striatum. This fit improved as the simulated model became more medicated (increased D2 receptor blockade). The relative improvement of this account correlated with patients’ medication dosage. In summary, by distilling the hypothetical neuropathology of schizophrenia into two simplified umbrella processes, and using a computational model to consider their effects within action selection, this work has successfully related patients’ fMRI activation to particular symptomatology and antipsychotic medication. This approach has the potential to improve patient care by enabling a neurobiological appreciation of their current illness state, and tailoring their medication level appropriately.