39 research outputs found
La visualisation : une application de la psychosynthèse auprès de groupes-classes de 2e et de 4e secondaire
Cette étude exploratoire tente de mieux comprendre la dynamique et l'impact d'une intervention pédagogique de type expérientiel sur la motivation générale de l'élève. Pour susciter le goût et le plaisir d'apprendre chez l'élève, il devient important de tendre à rejoindre l'apprenant* dans sa totalité. Ceci nous amène à nous questionner sur la pertinence d'introduire « l'expérience vécue » en pédagogie afin de parvenir à puiser dans les intérêts et le vécu de l'élève, une source de motivation importante à sa réussite scolaire. Cette recherche avait pour objectif de décrire les perceptions de l'élève relatives au processus de visualisation, comme élément facilitateur aux plans scolaire et personnel. Une intervention réalisée auprès de groupes-classes des deux cycles du secondaire, dans le cadre de matières différentes, permettait de faire vivre un processus expérientiel à l'élève et de recueillir ses perceptions par le biais d'un questionnaire. * Dans ce document, le générique masculin est utilisé pour désigner toute personne dans le seul but d'alléger le texte
Epilepsy in Dcx Knockout Mice Associated with Discrete Lamination Defects and Enhanced Excitability in the Hippocampus
Patients with Doublecortin (DCX) mutations have severe cortical malformations associated with mental retardation and epilepsy. Dcx knockout (KO) mice show no major isocortical abnormalities, but have discrete hippocampal defects. We questioned the functional consequences of these defects and report here that Dcx KO mice are hyperactive and exhibit spontaneous convulsive seizures. Changes in neuropeptide Y and calbindin expression, consistent with seizure occurrence, were detected in a large proportion of KO animals, and convulsants, including kainate and pentylenetetrazole, also induced seizures more readily in KO mice. We show that the dysplastic CA3 region in KO hippocampal slices generates sharp wave-like activities and possesses a lower threshold for epileptiform events. Video-EEG monitoring also demonstrated that spontaneous seizures were initiated in the hippocampus. Similarly, seizures in human patients mutated for DCX can show a primary involvement of the temporal lobe. In conclusion, seizures in Dcx KO mice are likely to be due to abnormal synaptic transmission involving heterotopic cells in the hippocampus and these mice may therefore provide a useful model to further study how lamination defects underlie the genesis of epileptiform activities
Clinical heterogeneity of neuro-inflammatory PET profiles in early Alzheimer’s disease
The relationship between neuroinflammation and cognition remains uncertain in early Alzheimer’s disease (AD). We performed a cross-sectional study to assess how neuroinflammation is related to cognition using TSPO PET imaging and a multi-domain neuropsychological assessment. A standard uptake value ratio (SUVR) analysis was performed to measure [18F]-DPA-714 binding using the cerebellar cortex or the whole brain as a (pseudo)reference region. Among 29 patients with early AD, the pattern of neuroinflammation was heterogeneous and exhibited no correlation with cognition at voxel-wise, regional or whole-brain level. The distribution of the SUVR values was independent of sex, APOE phenotype, early and late onset of symptoms and the presence of cerebral amyloid angiopathy. However, we were able to demonstrate a complex dissociation as some patients with similar PET pattern had opposed neuropsychological profiles while other patients with opposite PET profiles had similar neuropsychological presentation. Further studies are needed to explore how this heterogeneity impacts disease progression
Robust imaging of hippocampal inner structure at 7T: in vivo acquisition protocol and methodological choices
International audienceOBJECTIVE:Motion-robust multi-slab imaging of hippocampal inner structure in vivo at 7T.MATERIALS AND METHODS:Motion is a crucial issue for ultra-high resolution imaging, such as can be achieved with 7T MRI. An acquisition protocol was designed for imaging hippocampal inner structure at 7T. It relies on a compromise between anatomical details visibility and robustness to motion. In order to reduce acquisition time and motion artifacts, the full slab covering the hippocampus was split into separate slabs with lower acquisition time. A robust registration approach was implemented to combine the acquired slabs within a final 3D-consistent high-resolution slab covering the whole hippocampus. Evaluation was performed on 50 subjects overall, made of three groups of subjects acquired using three acquisition settings; it focused on three issues: visibility of hippocampal inner structure, robustness to motion artifacts and registration procedure performance.RESULTS:Overall, T2-weighted acquisitions with interleaved slabs proved robust. Multi-slab registration yielded high quality datasets in 96 % of the subjects, thus compatible with further analyses of hippocampal inner structure.CONCLUSION:Multi-slab acquisition and registration setting is efficient for reducing acquisition time and consequently motion artifacts for ultra-high resolution imaging of the inner structure of the hippocampus
Les banlieues de l’immigration
La banlieue québécoise a connu d’importantes mutations au cours des dernières décennies. Plusieurs se demandent si on ne devrait pas cesser de nommer ainsi des territoires qui ressemblent de plus en plus aux quartiers des villes centres. L’hétérogénéité sociale progressive des banlieues de l’après-guerre, nourrie entre autres par l’arrivée des immigrants, est un des facteurs qui inspirent ces débats. À partir de recherches réalisées dans des quartiers de la banlieue montréalaise et de certaines données statistiques, nous verrons comment l’immigration internationale se répartit en banlieue et proposerons une typologie de ses modes d’établissement. Puis nous nous interrogerons sur la manière dont l’immigration interpelle le modèle de la banlieue, en faisant référence notamment aux philosophies des « municipalités » de banlieue en matière d’intégration.Suburban Québec has undergone major changes over recent decades. Many observers wonder whether it might be appropriate to stop using the term ‘suburb’ to designate territories that are increasingly coming to resemble city-centre neighbourhoods. The progressive social heterogeneity of the post-war suburbs, sustained among other things by the arrival of immigrants, is one of the factors inspiring these debates. Based on research conducted on the suburban neighbourhoods of Montréal, and on certain statistical data, it will be seen how international immigration is spread out in suburban areas, and a typology for its modes of establishment will be proposed. This will be followed by an investigation of how immigration interacts with the suburban model, in particular by reference to the philosophies of the suburban “municipalities” regarding integration
Les choix résidentiels des ménages solos des quartiers centraux montréalais
INTRODUCTION Les ménages solos connaissent une croissance particulièrement forte dans la métropole québécoise. Le phénomène du vieillissement de la population n’y est sans doute pas étranger mais n’en constitue qu’un aspect. Or, une fois celui-ci mis de côté, on s’aperçoit que les significations sous-tendant ce phénomène semblent mal connues et donnent lieu à des considérations souvent alarmistes inspirées par les statistiques sur les taux de pauvreté des personnes seules [Pampalon et Raymond..
Doublecortin (DCX) is not Essential for Survival and Differentiation of Newborn Neurons in the Adult Mouse Dentate Gyrus
In the adult brain, expression of the microtubule-associated protein Doublecortin (DCX) is associated with neural progenitor cells (NPCs) that give rise to new neurons in the dentate gyrus. Many studies quantify the number of DCX-expressing cells as a proxy for the level of adult neurogenesis, yet no study has determined the effect of removing DCX from adult hippocampal NPCs. Here, we use a retroviral and inducible mouse transgenic approach to either knockdown or knockout DCX from adult NPCs in the dentate gyrus and examine how this affects cell survival and neuronal maturation. Our results demonstrate that shRNA-mediated knockdown of DCX or Cre-mediated recombination in floxed DCX mice does not alter hippocampal neurogenesis and does not change the neuronal fate of the NPCs. Together these findings show that the survival and maturation of adult-generated hippocampal neurons does not require DCX
Doublecortin Knockout Mice Show Normal Hippocampal-Dependent Memory Despite CA3 Lamination Defects
International audienceMutations in the human X-linked doublecortin gene (DCX) cause major neocortical disorganization associated with severe intellectual disability and intractable epilepsy. Although Dcx knockout (KO) mice exhibit normal isocortical development and architecture, they show lamination defects of the hippocampal pyramidal cell layer largely restricted to the CA3 region. Dcx-KO mice also exhibit interneuron abnormalities. As well as the interest of testing their general neurocognitive profile, Dcx-KO mice also provide a relatively unique model to assess the effects of a disorganized CA3 region on learning and memory. Based on its prominent anatomical and physiological features, the CA3 region is believed to contribute to rapid encoding of novel information, formation and storage of arbitrary associations, novelty detection, and short-term memory. We report here that Dcx-KO adult males exhibit remarkably preserved hippocampal-and CA3-dependant cognitive processes using a large battery of classical hippocampus related tests such as the Barnes maze, contextual fear conditioning, paired associate learning and object recognition. In addition, we show that hippocampal adult neurogenesis, in terms of proliferation, survival and differentiation of granule cells, is also remarkably preserved in Dcx-KO mice. In contrast, following social deprivation, Dcx-KO mice exhibit impaired social interaction and reduced aggressive behaviors. In addition, Dcx-KO mice show reduced behavioral lateralization. The Dcx-KO model thus reinforces the association of neuropsychiatric behavioral impairments with mouse models of intellectual disability
Evaluation of the potential of a new ribavirin analog impairing the dissemination of ovarian cancer cells
International audienceEpithelial ovarian cancers are insidious pathologies that give a poor prognosis due to their late discovery and the increasing emergence of chemoresistance. Development of small pharmacological anticancer molecules remains a major challenge. Ribavirin, usually used in the treatment of hepatitis C virus infections and more recently few cancers, has been a suggestion. However, Ribavirin has many side-effects, suggesting that the synthesis of analogs might be more appropriate. We have investigated the effect of a Ribavirin analog, SRO-91, on cancer cell behavioral characteristics considered as some of the hallmarks of cancer. Two human ovarian adenocarcinoma cell lines (SKOV3 and IGROV1) and normal cells (mesothelial and fibroblasts) have been used to compare the effects of SRO-91 with those of Ribavirin on cell behavior underlying tumor cell dissemination. SRO-91, like Ribavirin, inhibits proliferation, migration, clonogenicity and spheroids formation of cancer cells. Unlike Ribavirin, SRO-91 is preferentially toxic to cancer compared with normal cells. An in vitro physiologically relevant model showed that SRO-91, like Ribavirin or cisplatin, inhibits cancer cell implantation onto peritoneal mesothelium. In conclusion, SRO-91 analog effects on tumor dissemination and its safety regarding non-cancerous (normal) cells are encouraging findings a promising drug for the treatment of ovarian cancer