Networks at various levels of the nervous system coordinate different motor patterns such as respiration, eye or hand movements and locomotion. Intrinsic rhythm-generating networks that are located in the spinal cord generate motor behaviors that underlie locomotion in vertebrates. These networks give a continuous and measurable coordinated rhythmic motor output and are referred to as locomotor central pattern generators (CPGs). Characterization of the mammalian locomotor CPG and its molecular control is depending on the identification of participating neurons and neuronal populations. In this thesis I present work where we have studied the significance of subpopulations of neurons in the formation and function of the left-right circuitry. In summary, we show that the axon guidance receptor DCC has a central role in the formation of spinal neuronal circuitry underlying left-right coordination, and that both Netrin-1 and DCC are required for normal function of the locomotor CPG. Commissural interneurons (CINs), which send their axons across the ventral midline in the spinal cord, play a critical role in left–right coordination during locomotion. A complete loss of commissural axons in the spinal cord, as seen in the Robo3 null mutant mouse, resulted in uncoordinated fictional locomotor activity. Removing CIN connections from either dorsal or ventral neuronal populations led to a shift from alternation to strict synchronous locomotor activity. Inhibitory dI6 CIN have been suggested as promising candidate neurons in coordinating bilateral alternation circuitry. We have identified that Dmrt3, expressed in inhibitory dI6 CINs, is a crucial component for the normal development of coordinated locomotor movements in both horses and mice. We have also concluded that the prominent hopping phenotype seen in hop/hop mice is a result of abnormal developmental processes including induction from the notochord and Shh signaling. Together, these findings increase our knowledge about the flexibility in neuronal circuit development and further confirm the role of dI6 neurons in locomotor circuits.

abstract: This thesis offers a contrastive analysis of the causative alternation phenomenon in English and Standard Arabic variety. This phenomenon has received a lot of attention in the literature on argument structure. It has traditionally been presented in terms of the causativization of inchoative verbs/unaccusatives. It is argued here that this analysis conflicts with the way the causative alternation is molded in Arabic. Causative alternation in Arabic is not only limited to inchoative verbs, but it incorporates unergative verbs as well, which play a vital role in this alternation. The implication of this observation is that the different syntactic behaviors between English and Arabic may reflect people’s different perception of events and lead to different syntactic computation. Therefore, this thesis highlights the role of this subset of intransitives/anti-causatives in the Arabic causative alternation and answers one of the highly considered questions on the causative alternation; that is, which version of the alternation is the lexical base, and which one is derived? This thesis also reveals that there is some significant difference between English and Arabic in terms of the alternatability of unaccusative verbs. Therefore, this study shows that most of the Arabic unaccusative verbs, except denominal verbs, have a causative alternant. This thesis also addresses the vital role of the Arabic verbal template in clarifying this phenomenon. In sum, this thesis provides an overview of the semantic, syntactic, and morphological properties of Arabic verbs undergoing the causative alternation. Besides employing the researcher’s native-speaker intuition, the English/Arabic Lexicon Dictionary and Arabicorpora are consulted to support the validity of the argument. / Dissertation/Thesis / Masters Thesis English 2015

In current mammography practice, radiologists typically view mammograms in a symmetric, side-by-side, configuration in the belief that abnormalities will be made salient because they break the perceived symmetry. The literature on the use of symmetry as an aid to signal detection is limited and this thesis has taken a psychophysical approach to investigate the radiologist’s task of detecting a small mass (a blob) in paired mammogram backgrounds. Initial experiments used Gaussian white noise and synthetic mammogram backgrounds to test observer performance for the radiologist’s task using symmetric (side-by-side) displays and animated (the two images of a pair alternated sequentially in the same location) displays. The use of animated displays was then tested using real mammogram backgrounds in the subsequent experiments. The results showed that side-by-side presentation of paired images does not provide any benefit for the detection of a blob, whereas, alternated presentation enabled the observer to use the correlation present between the paired images to improve detection performance. The effect of alternation was not evident when applied to the task of detecting a small mass in real mammogram pairs and subsequent investigation suggested that the loss of effect resulted from the lack of scale invariance of real images. This meant that, regardless of the level of global correlation between two images, the localised correlation, at a region size reflecting the visual angle subtended by the fovea, was much lower. Thus, decorrelation by the visual system was ineffective and performance for the detection of a blob in the paired images was also ineffective. This thesis suggests that, whilst animated displays can be a powerful tool for the identification of differences between paired images, the underpinning mechanism of decorrelation makes them unsuited for mammograms where scale invariance means that correlation at local levels is a fraction of the global correlation level.

The aim of this thesis is to show that standard approaches to grammatical case fail to provide an explanatory account of such cases in Estonian. In Estonian, grammatical cases form a complex system of semantic contrasts, with the case-marking on nouns alternating with each other in certain constructions, even though the apparent grammatical functions of the noun phrases themselves are not changed. This thesis demonstrates that such alternations, and the differences in interpretation which they induce, are context dependent. This means that the semantic contrasts which the alternating grammatical cases express are available in some linguistic contexts and not in others, being dependent, among other factors, on the semantics of the casemarked noun and the semantics of the verb it occurs with. Hence, traditional approaches which treat grammatical case as markers of syntactic dependencies and account for associated semantic interpretations by matching cases directly to semantics not only fall short in predicting the distribution of cases in Estonian but also result in over-analysis due to the static nature of the theories which the standard approach to case marking comprises. On the basis of extensive data, it is argued that grammatical cases in Estonian have underspecified semantic content that is not truth-conditional, but inferential, i.e. it interacts with linguistic context and discourse. Inspired by the assumptions of Relevance Theory (Wilson & Sperber 1993, 2002, 2004) and Dynamic Syntax (Cann et al 2005), it is proposed that grammatical cases in Estonian provide procedural information: instead of taking cases to encode grammatical relations directly, and matching them to truth-conditional semantics, it is argued that it is more useful and explanatory to construe case marking in Estonian as providing information on how to process the case-marked expression and interpret it within an immediate discourse (or sentence). This means that grammatical cases in Estonian are seen to encode a heavily underspecified semantics which is enriched by pragmatic processes in context. In this way, certain problematic constructions in Estonian, such as transitive clauses in which the object is marked by either genitive or nominative, depending on number (often referred to as the accusative in the relevant literature, e.g. Ackerman & Moore 1999, 2001; Hiietam 2003, 2004) and constructions in which the nominative occurs on the object both with singular and plural nouns, are shown to have a unitary explanation.

Dans ce travail nous étudions la complexité de certains fragments du mu-calcul selon deux points de vue: l’un syntaxique et l’autre topologique. Dans la première partie nous adoptons le point de vue syntaxique afin d'étudier le comportement du mu-calcul sur des classes restreintes de modèles. Parmi d'autres résultats, nous montrons en particulier que sur les modèles transitifs toute propriété définissable par une formule du mu-calcul est définissable par une formule sans alternance de points fixes. Pour ce qui concerne la perspective topologique, nous montrons d'abord que sur les modèles transitifs la logique modale correspond au fragment borélien du mu-calcul. Ensuite nous donnons une description effective des hiérarchies de Borel et de Wadge d'un sous-fragment sans alternance de cette logique sur les arbres binaires et vérifions que pour ce fragment les points de vue topologique et syntaxique coïncident. / In this work we study the complexity of some fragments of the modal mu-calculus from two points of view: the syntactical and the topological. In the first part of the dissertation we adopt the syntactical point of view in order to study the behavior of this formalism on some restricted classes of models. Among other results, we show that on transitive transition systems, every mu-formula is logically equivalent to an alternation free formula. For what concerns the topological point of view, we first prove that on transitive models, the modal logic is exactly the Borel fragment of the modal mu-calculus. Then we provide an effective description of the Borel and Wadge hierarchies of a sub-fragment of the alternation free fragment of the mu-calculus on binary trees. Finally we verify that for this fragment the syntactical point of view and topological point of view coincide.

En 2004, la région Poitou-Charentes connait sa première alternance : l'équipe nouvelle affiche son intention de changer la politique régionale et présente « la démocratie participative » comme un choix de méthode d'action publique discriminant. En analysant conjointement les conditions d'importation et de mobilisation des idées et le travail de négociation, de mobilisation et de transaction entre les acteurs engagés à titre divers dans la production de l'action publique, nous mettons en évidence les dimensions idéologique, politique et institutionnelle de la fabrique de l'alternance, entendue comme le processus au cours duquel une équipe nouvellement élue tente de faire reconnaître son offre politique comme discriminante, de convertir l'organisation aux nouveaux objectifs qui lui sont assignés et de renégocier l'identité, les ressources et la valeur des porte-parole du territoire régional, institués par l'équipe précédente ; porte-parole avec lesquels et sur lesquels elle doit agir pour engager une action de transformation de la société locale et assoir sa position dans la compétition politique. En comparant trois dispositifs participatifs ("Budget participatif des lycées", "Jury citoyen d'évaluation de la politique régionale Transport et Mobilité" et "forum participatif sur l'eau"), nous analysons comment l'environnement régional, institué autour des politiques conduites par l'équipe précédente, se décompose et se recompose au cours de la mise en œuvre des procédures participatives qui mobilisent un public élargi de citoyens ordinaires. Ainsi, nous montrons comment ces instruments participatifs sont des vecteurs et des révélateurs d'une redéfinition du style politique et des catégories d'intervention publique régionaux. / In 2004, the Poitou-Charentes French region experienced its first political alternation. The new majority proclaimed its intention to transform local politics and displayed “participatory democracy” as a discriminating choice of public action methods. By analysing concomitantly the conditions of importation and mobilisation of political ideas and the process of negotiation, of mobilisation and of transaction which are taking place between the various actors involved in the production of public action, this works highlights the ideological, political and institutional dimensions of the making of the political alternation. The latter notion defines the process during which a newly-elected majority endeavours to make its political offer acknowledged as discriminating, to convert the institution to the new assigned objectives and to re-negotiate the identity, the resources and the value of the spokespersons of the regional territory. The new majority needs to work with and on these spokespersons, who had been promoted by the former political majority, in order to implement an action of transformation of the local society and assert its local political leadership. By comparing three ‘participatory’ devices ("high schools’ participatory budgets", "citizens' jury evaluating the ‘Transport and Mobility’ regional policy", and "participatory forum" on water issues), this work analyses how the regional framework, established around the policies run by the former political majority, are distorted and recomposed on the occasion of the implementation of these ‘participatory’ processes mobilizing a wide range of ordinary citizens. Thus, we show how these participatory tools are carriers and indicators of a re-definition of regional political style and categories of public intervention.

A Reunião de Passagem de Plantão de Enfermagem (RPPE) realizada no Hospital- Dia (HD) do Hospital das Clínicas da Faculdade de Medicina de Ribeirão Preto da Universidade de São Paulo, possui características particulares que a diferencia das reuniões tradicionais de passagem de plantão de enfermagem. Ela reune os integrantes da equipe interdisciplinar e todos têm a oportunidade tanto de informar sobre os pacientes assistidos no HD segundo os comportamentos apresentados nas suas atividades específicas, quanto de ouvir as informações dos demais integrantes. Trata-se, portanto, de um momento ímpar, reunindo motivos suficientes para levar a RPPE a objeto do presente estudo, que se caracteriza como quanti-qualitativo e teve como objetivos fazer um levantamento das freqüências dos integrantes da equipe interdisciplinar nessa reunião, dos relatos que fazem sobre observação e evolução dos pacientes e das decisões que tomam frente às ocorrências apresentadas. Para isso, foram utilizadas 20 RPPE em um período de tempo de dois meses, gravadas, transcritas na íntegra, realizadas sínteses e análise de conteúdo com apresentação descritiva dos resultados utilizando-se também de quadros. Os resultados mostraram uma participação maior de profissionais mais experientes na RPPE, talvez por eles coordenarem a maioria das atividades terapêuticas rotineiras do HD. Mostrou ainda, que a RPPE através do enfermeiro coordenador/facilitador, ofereceu oportunidades para os integrantes da equipe interdisciplinar informar sobre comportamentos dos pacientes nas suas atividades específicas, como também ouvir as informações dos outros. Ela mostrou-se cuidadosa, examinando sempre todos os pacientes semiinternados no HD, fazendo as observações e evoluções para cada um e tomando decisões sobre condutas a serem realizadas para aqueles que tinham necessidade no momento. A RPPE favoreceu trocas de experiências entre os profissionais das diversas áreas e contribuiu no processo ensino/aprendizagem do HD, que se constitui também em uma unidade de ensino. / The meeting for nursing shift alternation which happens at the Day Hospital in the Hospital das Clínicas da Faculdade de Medicina de Ribeirão Preto of São Paulo University, has particular characteristics which makes it different from the traditional nursing shift alternation meetings. It gathers members of the whole interdisciplinar team and each one, during this meeting, has the opportunity of informing about the patients under assistance at the Day Hospital regarding to their behaviour towards the specifics activities, as well as to hearing from the others. Therefore it is a single moment, combining sufficient reasons for bringing the nursing shift alternation meeting to object of the present study, which has a quantitative and qualitative character and has as objective to raise the interdisicplinar members frequency to those meetings, to report about observations and evolutions of patients, and decisions taken towards the presented situation. To obtain the result were used 20 nursing shift alternation meetings in a period of two months, which were recorded, integrally written-down, prepared content syntheses and analyses for descriptive results presentation also using panels. The results show an increased participation of experienced professionals in the nursing shift alternation meetings, maybe because they coordinate most of the therapeutical routine activities at the Day Hospital. It has also shown that the nursing shift alternation meeting, through the coordinator nurse, offers opportunities for all interdisciplinar team members to inform about their patients’ behaviour towards the specific activities, as well as to hearing from the others. The coordinator was careful, always examining all semi-hospitalized patient at the Day Hospital, making observation and evolution for each one, taking decisions about procedures to be adopted for those who were in need at that moment. The nursing shift alternation meeting gives support to exchanging experiences among professionals from different areas and contributes for the teaching/learning process at Day Hospital, which is also a teaching institution.

Made available in DSpace on 2017-07-21T20:31:45Z (GMT). No. of bitstreams: 1 IGNES AMORIM.pdf: 1526701 bytes, checksum: bf0434d8d52cab4d79d08cbd57025be0 (MD5) Previous issue date: 2008-12-10 / This research aims at investigating the alternative education (at school and at the academy) of the Landless Workers Movement, (Movimento dos Trabalhadores Rurais Sem Terra - MST) with the appliance of the “Alternation Pedagogy” to detect on this experience political pedagogical forms of resistance against exploit practices over peasants, workers and oppressed people in general. The goal of this dissertation is, specifically, the Alternation School with appeared in France in 1935 and that rouse similar experiences in Brazil from 1970, in certain environments were the intention was to educate a creative, militant and with cooperative conscientiousness person and, so, ecologic. The original pedagogical direction was put into the context of the peasants and their children and adopted MST’s groups (of the State of Paraná in special Lapa and Maringá cities) in order to mediate the response critical and practical of social transformation ideals of the peasants. The methodological procedures of the research included bibliographical exploration, qualitative approach, selecting documents, collection sets of interviews based on a semi-structured model with working students, monitors and leaders of the MST’s at their schools. Two reference names guided the research critic: Antonio Gramsci, on his defense that all people must join dialectally to construct the history and the progress of the nation, a new historical block that claims intelligence and action equally from the peasants in terms of surpassing of the oppressing hegemonies and Paulo Freire with his dialogue, autonomy, hope and resistance pedagogy are primordial to a really educative practice. It have been analyzed the historical condition of the peasant student, the MST reveled that the capitalistic model forces a oppression trajectory; the students seek for instruction but break familiar an cultural links and every time they back to the community they see themselves by a reality interpretation which cause alienation in face of their world and close the cooperative feelings. By the MST’s new educational experience the student learns dialectally the reality and, in this continuous teaching-leaning process, dialogue of knowledge, the student shifts his / her formation between two moments: the school moment and the familiar / communitarian. Following a methodology of observation and research the students are able to contextualize their socio-professional reality. The Alternation School on its experience assorted by the Via Campesina, support the subsistence agriculture, discuss the alimental autonomy of the planet and cooperate do disassembly the reductionism present in thoughts an practices peculiar of the inhuman bourgeoisie hegemony. On the steadiness of its pluralism this pedagogy seeks to educate men to work at the countryside and citizens with attitude. / Esta pesquisa tem como objetivo investigar a educação alternativa (escolar e acadêmica) do Movimento Sem Terra (MST) com aplicação da “Pedagogia da Alternância”; e detectar, nessa experiência, formas político-pedagógicas de resistência à exploração contra campesinos, proletários e oprimidos em geral. O objeto desta dissertação é, especificamente, a Escola de Alternância, que apareceu na França em 1935 e que suscitou experiências similares no Brasil, a partir de 1970, em meios onde pretendiam formar um sujeito criativo, militante, com consciência cooperativa e, pois, ecológica. A diretriz pedagógica originária, contextualizada, para rurais e seus filhos, foi assumida por grupos do MST-PR (em especial Lapa e Maringá), a fim de mediatizar a resposta crítico-prática aos ideais de transformação social dos campesinos. Os procedimentos metodológicos da pesquisa incluem a exploração bibliográfica e a abordagem qualitativa, selecionando documentos, reunindo depoimentos e entrevistas semi-estruturadas com alunos trabalhadores, com monitores e líderes do MST nas Escolas. Dois nomes referenciais fornecem a direção crítica da pesquisa: Antonio Gramsci, enquanto defende que todos se unam dialeticamente para construir a história e o progresso da nação, em novo bloco histórico que reclama a inteligência e a ação igualmente dos camponeses em vista da superação de hegemonias opressoras; e Paulo Freire, cuja pedagogia do diálogo, da autonomia, da esperança e da resistência sempre está muito presente às atividades do MST, e cujas propostas são fundamentais para a prática realmente educativa. Tendo analisado a condição histórica do aluno campesino, o MST pôs a descoberto que o modelo capitalista força a uma trajetória de opressão; o educando busca instrução, mas rompe com os laços familiares e culturais, e a cada vez, regressando à sua comunidade, se vê descaracterizado pela leitura da realidade que o aliena do seu mundo e o fecha a todo sentimento de cooperação. Pela nova experiência educativa do MST, o educando apreende dialeticamente a realidade e, no processo contínuo de ensino-aprendizagem, diálogo de saberes, alterna sua formação entre dois momentos ou períodos, do ambiente escolar e do ambiente familiar/comunitário; seguindo uma metodologia de observação e pesquisa, ele contextualiza da sua realidade sócio-profissional. A Escola de Alternância, na experiência absorvida pela Via Campesina, defende a agricultura de subsistência, discute a autonomia alimentar no planeta e coopera para desconstruir pensamento e prática reducionistas próprios da hegemonia burguesa inumana. Na firmeza do seu pluralismo, essa Pedagogia visa a formar homens para o trabalho no campo e cidadãos com posicionamento.

Submitted by Celso Magalhaes (celsomagalhaes@ufrrj.br) on 2018-09-11T12:50:42Z No. of bitstreams: 1 2016 - Eduardo Spitz de Carvalho.pdf: 2778180 bytes, checksum: 34e805f58061af534403ec60b6659541 (MD5) / Made available in DSpace on 2018-09-11T12:50:42Z (GMT). No. of bitstreams: 1 2016 - Eduardo Spitz de Carvalho.pdf: 2778180 bytes, checksum: 34e805f58061af534403ec60b6659541 (MD5) Previous issue date: 2016-03-31 / The municipality of Nova Friburgo is an important producer of brassica, in the Alto Rio Grande region, mainly cauliflower. This culture of great economic value has suffered with the incidence of clubroot causing huge losses, reaching 100% loss. For the prevention of the disease, it is necessary to understand that there is imbalance on the environment and that a change in the soil and crop management is crucial. In the region, young people have great importance in the production process and many of them study in technical courses offered by CEFFA (Centro Familiar de Forma??o por Altern?ncia) Col?gio Estadual Agr?cola (CEA) Rei Alberto I. The courses offered at the school work with the Pedagogy of Alternation. The aim of this study was to build with farmers and their children brassica crop management opportunities for minimizing impact of clubroot disease, with the association of local and academic knowledge. Therefore, we applied two questionnaires, one with 123 students from CEFFA CEA Rei Alberto I to the selection of the Production Units who grow brassicas and present incidence of clubroot, the other one, with 48 students, seeking to characterize the production systems, as for the topography, the main crops, and management strategies used to control the disease. At the end we selected eight production units (PUs) in different watersheds, distributed in the territorial space of the 3rd district, which were characterized by the history of clubroot in the production area, the forms of tillage, acidity correction and fertilization, seedlings source, planting season, crop rotation strategies, source of irrigation water and established strategies for coexistence with clubroot. Later, there were quality assessments of the soil, the health of crops and the potential for clubroot with students and their parents in each of the UPs. Soil samples were collected for fertility analysis. Then, there was a return of the reviews for farmers so they exchanged their joining knowledge. The management practices identified in the production units (PUs) evaluated in the 3rd District of Nova Friburgo- RJ have contributed to the spread and incidence of the disease. To live with the disease a change in the local production system design is necessary, pointing to new strategies regarding the encouragement of biotic and nutritional balance of soil and crop over the pathogen. The use of indicators to assess the local impact of potential hernia of cruciferous was efficient to point out the bottlenecks in the production of brassica system against the disease. The highly acidic pH and low Ca++ content in the soil, associated with frequent mechanization without cleaning the equipment might explain the high incidence of clubroot in the production units. The PUs require monitoring over time through evaluations of agro-ecosystems, using the tools presented in this study, as well as actions aimed at promoting the indicators towards sustainability, thus leading to the balance of soil, crops and biota / O munic?pio de Nova Friburgo ? importante produtor de br?ssicas na regi?o do Alto Rio Grande, principalmente, couve-flor. Esta cultura de grande valor econ?mico para o munic?pio vem sofrendo com a incid?ncia da h?rnia das cruc?feras com preju?zos de at? 100% de perda. Para preven??o da doen?a ? necess?rio o entendimento de que h? desequil?brio no ambiente e que a mudan?a no manejo do solo e da cultura ? imprescind?vel. Na regi?o, os jovens t?m grande import?ncia no processo de produ??o e grande parte desses estuda em cursos t?cnicos no CEFFA (Centro Familiar de Forma??o por Altern?ncia) Col?gio Estadual Agr?cola (CEA) Rei Alberto I, que funcionam com a Pedagogia da Altern?ncia. O objetivo desse trabalho foi construir participativamente junto aos agricultores e seus filhos possibilidades de manejo de cultivo de br?ssicas para o conv?vio com a doen?a h?rnia das cruc?feras, a partir da associa??o de conhecimentos locais e acad?micos. Para tanto, aplicou-se dois question?rios, um com os 123 alunos do CEFFA CEA Rei Alberto I para a sele??o das Unidades Produtivas que cultivam br?ssicas e que apresentam incid?ncia de h?rnia, o outro com 48 desses alunos, buscando caracterizar os sistemas de produ??o, quanto ao relevo, principais cultivos, e estrat?gias de manejo utilizadas para o controle da h?rnia. Ao final foram selecionadas oito unidades de produ??o (UPs) em diferentes microbacias, distribu?das no espa?o territorial do 3? distrito, as quais foram caracterizadas, quanto ao hist?rico da h?rnia das cruc?feras na ?rea de produ??o, formas de preparo do solo, corre??o da acidez e aduba??o, origem das mudas, ?poca do ano de plantio, estrat?gias de rota??o de cultivos, a origem da ?gua de irriga??o e as estrat?gias estabelecidas para a conviv?ncia com a h?rnia das cruc?feras. Posteriormente, foram avaliadas a qualidade do solo, a sanidade dos cultivos e a potencialidade para a h?rnia das cruc?feras, com os alunos e seus pais em cada UP. Foi coletado solos para an?lise de fertilidade. Posteriormente, foram retornadas as avalia??es para que os agricultores trocassem seus saberes. As pr?ticas de manejo identificadas nas unidades de produ??o (UPs) avaliadas do 3? Distrito de Nova Friburgo contribuem para dissemina??o e incid?ncia da doen?a. Para conviv?ncia com a doen?a deve ser mudada a concep??o do sistema produtivo local, apontando para novas estrat?gias para favorecimento do equil?brio bi?tico e nutricional do solo e das culturas em detrimento ao pat?geno. O uso de indicadores para avaliar a potencialidade de incid?ncia local da h?rnia das cruc?feras apontou os gargalos no sistema produtivo de br?ssicas em rela??o a doen?a. Os valores de pH, fortemente ?cidos, e os baixos teores de Ca no solo, associados a mecaniza??o frequente e sem limpeza dos equipamentos explicam a alta incid?ncia da h?rnia das cruc?feras nas unidades produtivas. As UPs necessitam acompanhamento ao longo do tempo, com avalia??es dos agroecossistemas, usando ferramentas como as apresentadas neste estudo, assim como a??es para promo??o dos indicadores no sentido da sustentabilidade, logo o equil?brio do solo, dos cultivos e da biota

Extensive evidence suggests that glucose has both positive and negative effects on memory and these effects likely involve an influence on the brain. For instance, direct infusions of glucose into the septum (MS) or hippocampus can enhance or impair memory. The present set of experiments attempted to determine the different conditions that dissociate the memory-enhancing and -impairing effects of glucose in rats. Specifically, these experiments examined the effects of glucose in spontaneous alternation, a measure of spatial working memory and shock avoidance, an index of emontional long-term memory. The results showed that the memory-impairing effects of MS infusions of glucose are not concentration-dependent. These data also indicated that the memory-impairing effects of MS glucose elevations are specific to gamma-aminobutyric acid GABA receptor activation but do not depend on increases in MS GABA synthesis or release. Importantly, we showed that the memory-impairing interaction between MS glucose and GABA agonists does not generalize to the hippocampus, suggesting the memory-modulating effects of glucose are brain region-dependent. We showed further that these brain region-dependent effects of glucose are not due to difference in basal extracellular glucose levels. Moreover, these findings showed that the memory-enhancing effects of hippocampus glucose override the memory-impairing interaction between MS glucose and GABA. These findings are important because they are the first to show that the memory-modulating effects of glucose are both neurotransmitter- and brain region-dependent. Furthermore, these findings provide preliminary evidence suggesting that the memory-impairing effects of MS glucose may involve compromised hippocampal function. These data also suggest the memory-impairing effects of MS co-infusions of glucose with GABA agonists likely involve an influence on the GABAergic SH projection. Finally, these findings demonstrate the mnemonic and neurochemical consequences of glucose in the MS and hippocampus, two brain regions affected by normal aging, Alzheimer’s disease, and diabetes.