Modelling emergent rhythmic activity in the cerebal cortex

A la portada consta: IDIBAPS Institut d'Investigacions Biomèdiques August Pi i SunyerThe brain, a natural adaptive system, can generate a rich dynamic repertoire of spontaneous activity even in the absence of stimulation. The spatiotemporal pattern of this spontaneous activity is determined by the brain state, which can range from highly synchronized to desynchronized states. During slow wave sleep, for example, the cortex operates in synchrony, defined by low-frequency fluctuations, known as slow oscillations (<1Hz). Conversely, during wakefulness, the cortex is characterized mainly by desynchronized activity, where low-frequency fluctuations are suppressed. Thus, an inherent property of the cerebral cortex is to transit between different states characterized by distinct spatiotemporal complexity patterns, varying in a large spectrum between synchronized and desynchronized activity. All these complex emergent patterns are the product of the interaction between tens of billions of neurons endowed with diverse ionic channels with complex biophysical properties. Nevertheless, what are the mechanisms behind these transitions? In this thesis, we sought to understand the mechanisms and properties behind slow oscillations, their modulation and their transitions towards wakefulness by employing experimental data analysis and computational models. We reveal the relevance of specific ionic channels and synaptic properties to maintaining the cortical state and also get out of it, and its spatiotemporal dynamics. Using a mean-field model, we also propose bridging neuronal spiking dynamics to a population description.El cerebro, un sistema adaptativo natural, es capaz de generar un amplio repertorio dinámico de actividad espontánea, incluso en ausencia de estímulos. La patrón espacio-temporal de esta actividad espontánea viene determinada por el estado cerebral, el cual puede variar de estados altamente sincronizados hasta estados muy desincronizados. Cuando en el sueño se entra en la fase de ondas lentas, por ejemplo, la corteza opera en sincronía, cuya actividad es definida por fluctuaciones de baja frecuencia, conocidas como oscilaciones lentas (<1Hz). En cambio, durante la vigilia, el córtex se caracteriza principalmente por tener una actividad desincronizada, donde las fluctuaciones de baja frecuencia desaparecen. Por lo tanto, una propiedad inherente de la corteza cerebral es transitar entre diferentes estados caracterizados por distintos patrones de complejidad espacio-temporal, los cuales se sitúan dentro del amplio espectro marcado por la actividad sincronizada y la desincronizada. Estos patrones emergentes son el producto de la interacción entre decenas de miles de millones de neuronas dotadas de múltiples y distintos canales iónicos con complejas propiedades biofísicas. Sin embargo, ¿cuáles son los mecanismos que regulan estas transiciones? En esta tesis tratamos de entender los mecanismos, propiedades y sus transiciones hacia la vigilia, que están detrás de las oscilaciones lentas a través del uso y análisis de datos experimentales y modelos computacionales. En ella describimos la importancia de los canales iónicos específicos y sus propiedades sinápticas tanto para mantener el estado cortical como para salir de él, estudiando así su dinámica espacio-temporal. Además, mediante el uso de un modelo de campo medio, proponemos establecer un puente que pueda describir la dinámica de disparos neuronales con una descripción general de la población neuronal.Postprint (published version

Puzzles Films: the nonlinear narrative of Christopher Nolan in the movie Dunkirk

A pesquisa realizada neste estudo concentra-se na construção de narrativas cinematográficas, mais especificamente no filme Dunkirk (2017), do cineasta Christopher Nolan, a qual se apresenta de maneira não linear, caracterizada por ser um puzzle film. O objeto empírico do estudo apresenta histórias de três personagens distintos que estão incluídos em um mesmo relato. Alguns fatos se repetem e ações passam na tela mais de uma vez, sob diferentes perspectivas. Nesse contexto, a pesquisa reconhece e compreende como estas técnicas narrativas são construídas. Para este fim, foi realizado um levantamento teórico com especificações de diferentes tipos de narrativas cinematográficas, atentando para questões temporais e espaciais.Palavras-chave: Cinema. Narrativa. Não-linearidade. Puzzle Film.The aim of this study focuses on the construction of cinematographic narratives, more specifically in the film Dunkirk (2017), by the filmmaker Christopher Nolan, which has a non-linear construction, characterized as puzzle film. The empirical object of the study presents three different temporal lines, from three distinct characters, but which are included in the same story. The story repeats itself and the actions are shown on the screen more than once, with different perspectives. In this context, the research seeks to recognize and how a non-linear narrative is constructed. To understand this construction, a theoretical survey was made with specifications of different types of cinematographic narratives.Keywords: Cinema. Narrative. Non-linearity. Puzzle Film

Study of Round Bodies: Conceptions and Praxis of a Didactic Sequence in Light of Guy Brousseau’s Theory

Background: Guy Brousseau’s theory of didactic situations has been considered an apparatus for the methodological structuring of didactic sequences configured in didactic and adidactic situations. Objectives: To investigate the contributions of the theory of didactic situations to the study of round bodies, focused on a praxis that meaningfully consolidates knowledge for the students. Design: We propose solving problem situations concerning the calculus of surface areas and volumes of round bodies using Cavalieri’s principle and Pappus’s theorems. Setting and participants: The research was conducted with two high school third-grade classes of a state institute of education located in the municipality of Júlio de Castilhos, RS, Brazil, with the participation of 25 students. Data collection and analysis: It was carried out through activities developed in the classroom and feedback given through Google Classroom. It was subsidised by the documental transcription of students’ records. Results: The research indicated that the didactic sequence development favoured intellectual autonomy and meaningful learning about the object of knowledge. Conclusions: The theory of didactic situations provided important subsidies for didactic organisation and analysis of the knowledge consolidation process involving the study of round bodies, indicating its application in the study of other mathematical objects in high school and higher education

Identification and neuromodulation of brain states to promote recovery of consciousness

Experimental and clinical studies of consciousness identify brain states (i.e., transient, relevant features of the brain associated with the state of consciousness) in a non-systematic manner and largely independent from the research into the induction of state changes. In this narrative review with a focus on patients with a disorder of consciousness (DoC), we synthesize advances on the identification of brain states associated with consciousness in animal models and physiological (sleep), pharmacological (anesthesia) and pathological (DoC) states of altered consciousness in human. We show that in reduced consciousness the frequencies in which the brain operates are slowed down and that the pattern of functional communication in the brain is sparser, less efficient, and less complex. The results also highlight damaged resting state networks, in particular the default mode network, decreased connectivity in long-range connections and in the thalamocortical loops. Next, we show that therapeutic approaches to treat DoC, through pharmacology (e.g., amantadine, zolpidem), and (non-)invasive brain stimulation (e.g., transcranial current stimulation, deep brain stimulation) have shown some effectiveness to promote consciousness recovery. It seems that these deteriorated features of conscious brain states may improve in response to these neuromodulation approaches, yet, targeting often remains non-specific and does not always lead to (behavioral) improvements. Furthermore, in silico model-based approaches allow the development of personalized assessment of the effect of treatment on brain-wide dynamics. Although still in infancy, the fields of brain state identification and neuromodulation of brain states in relation to consciousness are showing fascinating developments that, when united, might propel the development of new and better targeted techniques for DoC. For example, brain states could be identified in a predictive setting, and the theoretical and empirical testing (i.e., in animals, under anesthesia and patients with a DoC) of neuromodulation techniques to promote consciousness could be investigated. This review further helps to identify where challenges and opportunities lay for the maturation of brain state research in the context of states of consciousness. Finally, it aids in recognizing possibilities and obstacles for the clinical translation of these diagnostic techniques and neuromodulation treatment options across both the multi-modal and multi-species approaches outlined throughout the review. This paper presents interactive figures, supported by the Live Paper initiative of the Human Brain Project, enabling the interaction with data and figures illustrating the concepts in the paper through EBRAINS (go to https://wiki.ebrains.eu/bin/view/Collabs/live-paper-states-altered-consciousness and get started with an EBRAINS account).NA is research fellow, OG is Research Associate, and SL is research director at FRS-FNRS. JA is postdoctoral fellow at the FWO. The study was further supported by the University and University Hospital of Liège, the BIAL Foundation, the Belgian National Funds for Scientific Research (FRS-FNRS), the European Union's Horizon 2020 Framework Programme for Research and Innovation under the Specific Grant Agreement No. 945539 (Human Brain Project SGA3), the FNRS PDR project (T.0134.21), the ERA-Net FLAG-ERA JTC2021 project ModelDXConsciousness (Human Brain Project Partnering Project), the fund Generet, the King Baudouin Foundation, the Télévie Foundation, the European Space Agency (ESA) and the Belgian Federal Science Policy Office (BELSPO) in the framework of the PRODEX Programme, the Public Utility Foundation 'Université Européenne du Travail', "Fondazione Europea di Ricerca Biomedica", the BIAL Foundation, the Mind Science Foundation, the European Commission, the Fondation Leon Fredericq, the Mind-Care foundation, the DOCMA project (EU-H2020-MSCA–RISE–778234), the National Natural Science Foundation of China (Joint Research Project 81471100) and the European Foundation of Biomedical Research FERB Onlus

La renovación de la palabra en el bicentenario de la Argentina : los colores de la mirada lingüística

El libro reúne trabajos en los que se exponen resultados de investigaciones presentadas por investigadores de Argentina, Chile, Brasil, España, Italia y Alemania en el XII Congreso de la Sociedad Argentina de Lingüística (SAL), Bicentenario: la renovación de la palabra, realizado en Mendoza, Argentina, entre el 6 y el 9 de abril de 2010. Las temáticas abordadas en los 167 capítulos muestran las grandes líneas de investigación que se desarrollan fundamentalmente en nuestro país, pero también en los otros países mencionados arriba, y señalan además las áreas que recién se inician, con poca tradición en nuestro país y que deberían fomentarse. Los trabajos aquí publicados se enmarcan dentro de las siguientes disciplinas y/o campos de investigación: Fonología, Sintaxis, Semántica y Pragmática, Lingüística Cognitiva, Análisis del Discurso, Psicolingüística, Adquisición de la Lengua, Sociolingüística y Dialectología, Didáctica de la lengua, Lingüística Aplicada, Lingüística Computacional, Historia de la Lengua y la Lingüística, Lenguas Aborígenes, Filosofía del Lenguaje, Lexicología y Terminología

Formação do raciocínio estatístico na conceptualização da estimação estatística : estudo exploratório de um dispositivo pedagógico no ensino superior

Statistical data are present in various media of society and are indispensable in scientific fields and in the training of the modern citizen. For this reason, statistics are discussed from basic education in Brazil and remain present at other levels of education. Our study is in the field of statistics education at the level of higher education and is part of the line of research focused on the teaching and learning of statistical concepts, especially related to the concepts of estimation. statistical. The work, developed as part of a qualitative and quantitative research, aimed to identify how the formation of statistical reasoning is achieved by the conceptualization of statistical estimation. From a sample of 81 undergraduate university students in the social sciences and technology sciences at a higher education institution in the city of Santa Maria, State of Rio Grande do Sul, in Brazil. As theoretical references, we use Conceptual Field Theory and the exploitation of several researches on statistical skills: literacy, thinking and statistical reasoning. We base our exploration on data constructed using two questionnaires applied in statistical disciplines, before and after having addressed, in progress, the contents concerning the statistical estimation. The questionnaires were organized with questions based on problematic situations related to statistical estimation and questions related to the student'sreport to statistics and statistics. For data processing, analysis and interpretation, statistical computer tools have been used in the theoretical framework of implicative statistical analysis (ASI), with the help of CHIC software, and in classical statistics for descriptive and inferential statistical analysis of SPAD software. The results show that students who have better relations with statistics use the concepts learned in a more satisfactory way. The orientation of these relationships with statistics can influence the formation of statistical reasoning, mainly because of mathematical problems.Keywords: Statistical skills. StatisticalLes données statistiques sont présentes dans divers médias de la société et sont indispensables dans les domaines scientifiques et dans la formation du citoyen moderne. Pour cette raison, la statistique est abordée dès l’éducation de base au Brésil et reste présente à d’autres niveaux d’enseignement. Notre étude se situe dans le domaine de l’enseignement de la statistique au niveau de l’enseignement supérieur et fait partie de la ligne de recherche axée sur l’enseignement et l’apprentissage de concepts statistiques, plus particulièrement liés aux concepts d’estimation statistique. Les travaux, développés dans le cadre d'une recherche qualitative et quantitative, ont visé à identifier comment se réalise la formation duraisonnement statistique par la conceptualisation de l'estimation statistique. A partir d’un échantillon de 81 étudiants des cours de premier cycle universitaire dans les domaines des sciences sociales et des sciences technologiques d'un établissement d’enseignement supérieur de la ville de Santa Maria, dans l'état de Rio Grande do Sul, au Brésil. Comme références théoriques, nous utilisons la Théorie des Champs Conceptuels et l'exploitation de plusieurs recherches portant sur les compétences statistiques: littéracie, pensée et raisonnement statistique. Nous basons notre exploration sur des données construites à l'aide de deux questionnaires appliqués dans des disciplines statistiques, avant et après avoir abordé, en cours, le contenu portant sur l'estimation statistique. Les questionnaires ont été organisés avec des questions basées sur des situations problématiques liées à l'estimation statistique et des questions liées au rapport de l'étudiant à la statistique et aux statistiques. Pour le traitement, l'analyse et l'interprétation des données, des outils informatiques statistiques ont été utilisés dans le cadre théorique de l'analyse statistique implicative (ASI), avec l'aide du logiciel CHIC et, dans celui de la statistique classique, pour les analyses statistiques descriptives et inférentielles, du logiciel SPAD. Les résultats montrent que les étudiants ayant de meilleures relations avec la statistique et les statistiques mobilisent les concepts appris de manière plus satisfaisante. L’orientation de ces relations avec la statistique et les statistiques peut influencer la formation du raisonnement statistique, principalement en raison de problèmes mathématiques.Os dados estatísticos estão presentes em diversos meios da sociedade e são indispensáveis nos campos científicos e na formação do cidadão moderno. Por essa razão, a estatística é abordada no Brasil a partir da educação básica e permanece presente em outros níveis de ensino. Nosso estudo está situado no campo da Educação Estatística no Ensino Superior e se insere na linha de investigação voltada ao ensino e aprendizagem de conceitos da estatística, mais particularmente relacionados aos conceitos de estimação estatística. O trabalho, desenvolvido no contexto de uma pesquisa qualitativa e quantitativa, teve como objetivo identificar como se dá a formação do raciocínio estatístico por meio da conceptualização da estimação estatística. Observamos uma amostra de 81 estudantes oriundos de cursos de graduação das áreas de Ciências Socias e Ciências Tecnológicas, de uma instituição comunitária da cidade de Santa Maria, estado do Rio Grande do Sul, Brasil. Como referencial teórico utilizamos a Teoria dos Campos Conceituais e a exploração de diversas pesquisas que tratam sobre as competências estatísticas: letramento, pensamento e raciocínio estatísticos. Baseamos nossa exploração em dados construídos por meio de dois questionários que foram aplicados em disciplinas de estatística, antes e depois do conteúdo de estimação estatística ser explorado em sala de aula. Os questionários foram organizados com questões baseadas em situações-problema relacionadas com a estimação estatística e por questões pertinentes quanto a relação do estudante com a estatística. Para o tratamento, análise e interpretação dos dados, ferramentas computacionais estatísticas foram utilizadas no quadro teórico da análise estatística implicativa (ASI), com o apoio do software CHIC e, na estatística clássica, para análises estatísticas descritivas e inferenciais, o software SPAD. Os resultados obtidos mostram que os estudantes que possuem melhores relações com a estatística utilizam os conceitos aprendidos de forma mais satisfatória. A orientação dessas relações com a estatística podem influenciar na formação do raciocínio estatístico, principalmente em razão de problemas matemáticos.Palavras-chave: Competência

Contribuições da engenharia didática para o ensino e aprendizagem de funções de várias variáveis reais

Made available in DSpace on 2018-06-27T19:13:03Z (GMT). No. of bitstreams: 3 Leonardo Dalla Porta.pdf: 7045647 bytes, checksum: 0863feac3bb4488ee608a8488af25b02 (MD5) Leonardo Dalla Porta.pdf.txt: 159812 bytes, checksum: eb05a9a089c5fe067fa047937955a231 (MD5) Leonardo Dalla Porta.pdf.jpg: 2861 bytes, checksum: 4b954d84f7a4bfb3f7e6ab3eb0135106 (MD5) Previous issue date: 2014-02-26Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorEsta pesquisa tem como objetivo analisar as contribuições da Engenharia Didática para a melhoria do ensino e da aprendizagem de funções de várias variáveis reais, com a utilização do software Maple. A pesquisa foi realizada com alunos do Curso de Licenciatura em Matemática matriculados na disciplina de Cálculo III do Centro Universitário Franciscano em Santa Maria, RS. Os estudos preliminares, com a aplicação de um teste diagnóstico, mostraram as dificuldades dos alunos na construção do conceito de função de uma variável real. A partir da análise preliminar foi elaborada uma sequência de ensino, baseada em 3 unidades didáticas que abordaram, respectivamente, a construção do conceito de função de uma variável real, a construção do conceito de funções de várias variáveis reais e a construção do conceito de funções de várias variáveis reais com a manipulação do software Maple. As unidades didáticas foram constituídas de questões com diferentes pontos de vista em relação a funções, tais como: pela descrição em palavras, numericamente através de uma tabela de valores, algebricamente por fórmulas explícitas e visualmente por gráficos. Os resultados da investigação demonstraram que a sequência de ensino proposta contribuiu para a compreensão do conceito de funções e a utilização do software Maple possibilitou que os alunos inferissem e comprovassem suas asserções construindo seus próprios exemplos e, assim, participando do processo de aprendizagem

La formation du raisonnement statistique à travers la conceptualisation de l'estimation statistique : étude exploratoire d'un dispositif pédagogique dans l'enseignement supérieur

Les données statistiques sont présentes dans divers médias de la société et sont indispensables dans les domaines scientifiques et dans la formation du citoyen moderne. Pour cette raison, la statistique est abordée dès l’éducation de base au Brésil et reste présente à d’autres niveaux d’enseignement. Notre étude se situe dans le domaine de l’enseignement de la statistique au niveau de l’enseignement supérieur et fait partie de la ligne de recherche axée sur l’enseignement et l’apprentissage de concepts statistiques, plus particulièrement liés aux concepts d’estimation statistique. Les travaux, développés dans le cadre d'une recherche qualitative et quantitative, ont visé à identifier comment se réalise la formation duraisonnement statistique par la conceptualisation de l'estimation statistique. A partir d’un échantillon de 81 étudiants des cours de premier cycle universitaire dans les domaines des sciences sociales et des sciences technologiques d'un établissement d’enseignement supérieur de la ville de Santa Maria, dans l'état de Rio Grande do Sul, au Brésil. Comme références théoriques, nous utilisons la Théorie des Champs Conceptuels et l'exploitation de plusieurs recherches portant sur les compétences statistiques: littéracie, pensée et raisonnement statistique. Nous basons notre exploration sur des données construites à l'aide de deux questionnaires appliqués dans des disciplines statistiques, avant et après avoir abordé, en cours, le contenu portant sur l'estimation statistique. Les questionnaires ont été organisés avec des questions basées sur des situations problématiques liées à l'estimation statistique et des questions liées au rapport de l'étudiant à la statistique et aux statistiques. Pour le traitement, l'analyse et l'interprétation des données, des outils informatiques statistiques ont été utilisés dans le cadre théorique de l'analyse statistique implicative (ASI), avec l'aide du logiciel CHIC et, dans celui de la statistique classique, pour les analyses statistiques descriptives et inférentielles, du logiciel SPAD. Les résultats montrent que les étudiants ayant de meilleures relations avec la statistique et les statistiques mobilisent les concepts appris de manière plus satisfaisante. L’orientation de ces relations avec la statistique et les statistiques peut influencer la formation du raisonnement statistique, principalement en raison de problèmes mathématiques.Statistical data are present in various media of society and are indispensable in scientific fields and in the training of the modern citizen. For this reason, statistics are discussed from basic education in Brazil and remain present at other levels of education. Our study is in the field of statistics education at the level of higher education and is part of the line of research focused on the teaching and learning of statistical concepts, especially related to the concepts of estimation. statistical. The work, developed as part of a qualitative and quantitative research, aimed to identify how the formation of statistical reasoning is achieved by the conceptualization of statistical estimation. From a sample of 81 undergraduate university students in the social sciences and technology sciences at a higher education institution in the city of Santa Maria, State of Rio Grande do Sul, in Brazil. As theoretical references, we use Conceptual Field Theory and the exploitation of several researches on statistical skills: literacy, thinking and statistical reasoning. We base our exploration on data constructed using two questionnaires applied in statistical disciplines, before and after having addressed, in progress, the contents concerning the statistical estimation. The questionnaires were organized with questions based on problematic situations related to statistical estimation and questions related to the student'sreport to statistics and statistics. For data processing, analysis and interpretation, statistical computer tools have been used in the theoretical framework of implicative statistical analysis (ASI), with the help of CHIC software, and in classical statistics for descriptive and inferential statistical analysis of SPAD software. The results show that students who have better relations with statistics use the concepts learned in a more satisfactory way. The orientation of these relationships with statistics can influence the formation of statistical reasoning, mainly because of mathematical problems.Keywords: Statistical skills. StatisticalOs dados estatísticos estão presentes em diversos meios da sociedade e são indispensáveis nos campos científicos e na formação do cidadão moderno. Por essa razão, a estatística é abordada no Brasil a partir da educação básica e permanece presente em outros níveis de ensino. Nosso estudo está situado no campo da Educação Estatística no Ensino Superior e se insere na linha de investigação voltada ao ensino e aprendizagem de conceitos da estatística, mais particularmente relacionados aos conceitos de estimação estatística. O trabalho, desenvolvido no contexto de uma pesquisa qualitativa e quantitativa, teve como objetivo identificar como se dá a formação do raciocínio estatístico por meio da conceptualização da estimação estatística. Observamos uma amostra de 81 estudantes oriundos de cursos de graduação das áreas de Ciências Socias e Ciências Tecnológicas, de uma instituição comunitária da cidade de Santa Maria, estado do Rio Grande do Sul, Brasil. Como referencial teórico utilizamos a Teoria dos Campos Conceituais e a exploração de diversas pesquisas que tratam sobre as competências estatísticas: letramento, pensamento e raciocínio estatísticos. Baseamos nossa exploração em dados construídos por meio de dois questionários que foram aplicados em disciplinas de estatística, antes e depois do conteúdo de estimação estatística ser explorado em sala de aula. Os questionários foram organizados com questões baseadas em situações-problema relacionadas com a estimação estatística e por questões pertinentes quanto a relação do estudante com a estatística. Para o tratamento, análise e interpretação dos dados, ferramentas computacionais estatísticas foram utilizadas no quadro teórico da análise estatística implicativa (ASI), com o apoio do software CHIC e, na estatística clássica, para análises estatísticas descritivas e inferenciais, o software SPAD. Os resultados obtidos mostram que os estudantes que possuem melhores relações com a estatística utilizam os conceitos aprendidos de forma mais satisfatória. A orientação dessas relações com a estatística podem influenciar na formação do raciocínio estatístico, principalmente em razão de problemas matemáticos.Palavras-chave: Competência

Modeling neuronal avalanches and long-range temporal correlations at the emergence of collective oscillations: Continuously varying exponents mimic M/EEG results.

We revisit the CROS ("CRitical OScillations") model which was recently proposed as an attempt to reproduce both scale-invariant neuronal avalanches and long-range temporal correlations. With excitatory and inhibitory stochastic neurons locally connected in a two-dimensional disordered network, the model exhibits a transition where alpha-band oscillations emerge. Precisely at the transition, the fluctuations of the network activity have nontrivial detrended fluctuation analysis (DFA) exponents, and avalanches (defined as supra-threshold activity) have power law distributions of size and duration. We show that, differently from previous results, the exponents governing the distributions of avalanche size and duration are not necessarily those of the mean-field directed percolation universality class (3/2 and 2, respectively). Instead, in a narrow region of parameter space, avalanche exponents obtained via a maximum-likelihood estimator vary continuously and follow a linear relation, in good agreement with results obtained from M/EEG data. In that region, moreover, the values of avalanche and DFA exponents display a spread with positive correlations, reproducing human MEG results