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See detailConnectome-based classification of BDNF Met allele carriers
Ziegler, Erik ULg; Foret, Ariane; Mascetti, Laura ULg et al

Poster (2013, June)

Secretion of brain-derived neurotrophic factor (BDNF) is essential for synaptic plasticity in the central nervous system during neurodevelopment [Huang]. A common human non-synonymous SNIP in the BDNF ... [more ▼]

Secretion of brain-derived neurotrophic factor (BDNF) is essential for synaptic plasticity in the central nervous system during neurodevelopment [Huang]. A common human non-synonymous SNIP in the BDNF gene (Val66Met, rs6265) decreases activity-dependent BDNF release in neurons transfected with the human A allele (Met-BDNF). We reasoned that the persistent differential activity-dependent BDNF release implied by this polymorphism should also be associated with differences in adult brain structure. The study population comprised 36 healthy subjects (aged 18-25): 15 (9 male) were identified as carrying the Met allele (“Met carrier” group) and 21 (9 male) were homozygotes for the Val allele (“Val/Val” group). The groups did not vary significantly in IQ, age nor scores for a battery of psychological tests. A high-resolution T1-weighted image (sMRI), 7 unweighted (b=0) and a set of diffusion-weighted (b=1000) images using 61 non-collinear directional gradients were acquired for each subject. The processing workflow relied on several pieces of software and was developed in Python and Nipype. The sMRIs were segmented using the automated labeling of Freesurfer [Desikan] and further parcellated using the Lausanne2008 atlas into 1015 regions of interest (ROIs) [Cammoun]. DWIs were corrected for image distortions (due to eddy currents) using linear coregistration functions from FSL [Smith]. Fractional anisotropy maps were generated, and a few single-fiber (high FA) voxels were used to estimate the spherical harmonic coefficients (order 8) of the response function from the DWIs [Tournier]. Then orientation distribution functions were obtained at each voxel. Probabilistic tractography was performed throughout the whole brain using seeds from subject-specific white-matter masks and a predefined number of tracts (300,000), see Fig. 1. The tracks were affine-transformed into the subject's structural space with Dipy [Garyfallidis]. Connectome mapping was performed by considering every contact point between each tract and the outlined ROIs (unlike in [Hagmann]): the connectivity matrix was incremented every time a single fiber traversed between any two ROIs. We trained a Gaussian Process Classifier [Rasmussen] (interfaced by PRoNTo [Schrouff]) on these connectivity matrices. The accuracy and generalization ability of the classification were assessed with a leave-one-subject-out cross-validation procedure. With this linear kernel method weights were also obtained indicating the contribution to the classification output (in favor of either genotypic group) of each edge in the network. The same method was employed to discriminate features related to the subjects' gender and genotype for the ADA gene. The classifier was able to discriminate between Val/Val and Met carriers with 86.1% balanced accuracy. The predictive value for the Val/Val and Met carrier groups were 94.4% (p=0.001) and 77.8% (p=0.003), respectively. In Fig. 2 the weights obtained by the classifier are visualized as edges in the brain network. For the classifier trained to identify gender or the subjects' ADA genotype, the global accuracy reached 63.9% (n.s.) and 58.3% (n.s.) respectively. Using high-resolution connectome mapping from normal young healthy human volunteers grouped based on the Met allele of the BNDF gene, we show that the BDNF genotype of an individual can be significantly identified from his structural brain wiring. These differences appear specific to this allele; no such difference could be found for the polymorphism in the ADA gene, or even for gender. We propose that the decreased availability of BDNF leads to deficits in axonal maintenance in Met carriers, and that this produces mesoscale changes in white matter architecture. Acknowledgements: the FNRS, the ULg, the Queen Elisabeth Medical Foundation, the Léon Fredericq Foundation, the Belgian Inter-University Attraction Program, the Welbio program, and the MCITN in Neurophysics (PITN-GA-2009-238593). Cammoun L. et al. (2011), ‘Mapping the human connectome at multiple scales with diffusion spectrum MRI’, J Neuroscience Methods, 203:386–397. Desikan R.S. et al. (2006), ‘An automated labeling system for subdividing the human cerebral cortex on MRI scans into gyral based regions of interest’, Neuroimage, 31:968-980. Hagmann P. et al. (2008), ‘Mapping the structural core of human cerebral cortex’, PLoS Biology, 6:e159 Huang E.J., Reichardt L.F. (2001), ‘Neurotrophins: roles in neuronal development and function’, Annual Review of Neuroscience, 24:677-736. Garyfallidis E. et al. (2011), ‘Dipy - a novel software library for diffusion MR and tractography’, 17th Annual Meeting of the Organization for Human Brain Mapping. http://nipy.sourceforge.net/dipy/ Rasmussen C.E. (2006), Gaussian processes for machine learning. Schrouff J. et al. (2012), ‘PRoNTo: Pattern Recognition for Neuroimaging Toolbox’, 18th Annual Meeting of the Organization for Human Brain Mapping. http://www.mlnl.cs.ucl.ac.uk/pronto Smith S.M. et al. (2004), ‘Advances in functional and structural MR image analysis and implementation as FSL’, Neuroimage, 23 Suppl 1:S208-S219. Tournier J.D., et al. (2007), ‘Robust determination of the fibre orientation distribution in diffusion MRI: non-negativity constrained super-resolved spherical deconvolution’, Neuroimage, 35:1459-1472. [less ▲]

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See detailThe Conners Parent Rating Scale: Confirmatory factorial analysis on preliminary data in a sample of 5-10 years old Belgian French Speaking Children
Catale, Corinne ULg; Meulemans, Thierry ULg; Lejeune, Caroline ULg et al

in Book of Abstracts (2012)

Introduction The Conners Parent Rating Scale-48 items (CPRS) is one of the most used behavioral scales in clinical and research settings with children suffering from neurodevelopmental disorders, and ... [more ▼]

Introduction The Conners Parent Rating Scale-48 items (CPRS) is one of the most used behavioral scales in clinical and research settings with children suffering from neurodevelopmental disorders, and particularly with children with Attention Deficit and Hyperactivity Disorder (ADHD). This scale provides an interesting qualitative and quantitative picture of the emotional and behavioural children’s attitude by including five subscales assessing conduct problem, learning problem, anxiety, impulsive/hyperactive behaviour and psychosomatic feelings (e.g., Goyette, Conners, & Ulrich, 1978). Previous versions of this scale were developed to contribute to the identification of hyperkinetic children and evaluate treatment efficiency. To our knowledge, no study has verified the factor structure of the French version of the CPRS. In this context, the principal aims of this study were to verify the five-factor structure of the French version of the CPRS and therefore to provide preliminary culturally adapted normative data for Belgian French-speaking children aged from 5 to 10 years old. Method The CPRS for parents was distributed in several schools in the region of Liège (Belgium). A total of 157 parents of normally developing 5-10 years old children participated in this study (Mean age: 7.94 years, SD: 2.01). Exclusion criteria for participation were a history of traumatic brain injury or neurological, developmental, learning, or psychiatric disorders. Results We carried out a Confirmatory Factor Analysis (CFA) using LISREL 8.80 (Jöreskog & Sörbom, 2006) to examine the factor structure of the French version of the CPRS. We tested the five-factor structure found in Goyette, Conners, and Ulrich (1978) with the English version including the five following subscales: [i] Conduct problem, [ii] Learning problem, [iii] Psychosomatic, [iv] Impulsive-hyperactive, and [v] Anxiety. To evaluate the fit of this model, different goodness-of-fit indexes were employed: (1) the chi2 value, (2) the Root Mean Square Error of Approximation (RMSEA; Browne & Cudeck, 1989), and (3) the Comparative Fit Index (CFI; Bentler, 1990). Generally, the fitness index is calculated from the value of the chi-square divided by the degrees of freedom. A value of chi2/df of less than 2 is considered to be an indication of an adequate fit. The RMSEA indicates a ‘good’ approximation if it is less than .05. A RMSEA between .05 and .08 reflects a ‘reasonable’ approximation, and a RMSEA greater than .08 indicates poor approximation. In line with Goyette, Conners, and Ulrich (1978), a five-factor model was constructed in which the items of the CPRS were hypothesized to reflect these factors. The chi-square of the model was not significant, chi2 (199) = 230.626, p > .05. The chi2/df ratio is 1.15, which indicates an adequate fit. For the other fit indices, we obtained a RMSEA of .07. The combination of these indices indicated an acceptable fit for the model tested. The standard item alpha for the whole-scale was .82. The reliability coefficient (Cronbach’s alpha) for each of the subscales ranged from .63 to .80 (Mean: .72). The coefficients confirmed the good internal reliability of the inventory. Discussion The principal aim of this study was to validate the five-factor structure of the French adaptation of the CPRS in Belgian French-speaking children. Interestingly, the CFA showed that, like the original version, the French adaptation of the CPRS presents good psychometric characteristics. More interestingly, the CFA confirmed that the 48-item scale of the French version of the CPRS specifically assessed the five different children’s behaviours described above. Furthermore, this study provides cultural-adapted normative data for Belgian French-speaking children. Future research will be necessary to examine to what extent this questionnaire can discriminate between children with ADHD and normally developing children. [less ▲]

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See detailConnexin expression and gap junctional intercellular communication in human first trimester trophoblast
Cronier, L.; Defamie, N.; Dupays, L. et al

in Molecular Human Reproduction (2002), 8(11), 1005-1013

Connexin (Cx) expression and gap junctional intercellular communication (GJIC) are involved in development and differentiation processes, and recently mutation of connexin genes has been implicated in ... [more ▼]

Connexin (Cx) expression and gap junctional intercellular communication (GJIC) are involved in development and differentiation processes, and recently mutation of connexin genes has been implicated in pathologies. In the human placenta, two distinct differentiation pathways of cytotrophoblastic cells coexist and lead to a fusion phenotype (villous trophoblast) and a proliferative/invasive phenotype (extravillous trophoblast). Here we characterized in situ and in vitro the expression of Cx transcripts and proteins in the villous and extravillous trophoblast of first trimester placenta. In addition, the GJIC functionality was investigated using the gap-fluorescence recovery after photobleaching (gap-FRAP) method. We demonstrated in the villous trophoblast the presence of Cx43 mRNA and of Cx43 protein localized between cytotrophoblastic cells and between cytotrophoblastic cells and syncytiotrophoblast. In vitro, a transient functional gap junctional intertrophoblastic communication was demonstrated during the trophoblast fusion leading to the multinucleated syncytiotrophoblast. During the proliferative process of the extravillous trophoblast, Cx40 is expressed in the proximal part of the cell columns. When cytotrophoblastic cells were cultured on Matrigel(R) for 2 days, alpha5beta1 integrin expression was observed concomitant with the presence of Cx40 mRNA and of Cx40 protein between the cells. No evidence for a GJIC was detected in this induced extravillous phenotype. In addition, Cx32 was detected between some aggregated cells after 72 h of culture. Our data show that the presence of Cx43 allows an inter-trophoblastic GJIC and is associated with the fusion process leading to the villous syncytiotrophoblast and that the presence of Cx40 does not allow GJIC and is associated with the extravillous phenotype. [less ▲]

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See detailLa connexion entre la politique de coopération au développement et la politique étrangère : le cas de la Roumanie dans la région de la mer Noire
Teclu, Codrat Alin ULg

in Wintgens, Sophie; Grandjean, Geoffrey (Eds.) Acteurs émergents. Perspectives pour la gouvernance mondiale (2013)

Suite à son adhésion à l’Union Européenne le 1er janvier 2007, la Roumanie doit se doter d’une politique de coopération au développement afin d’être en conformité avec l’acquis communautaire. Le présent ... [more ▼]

Suite à son adhésion à l’Union Européenne le 1er janvier 2007, la Roumanie doit se doter d’une politique de coopération au développement afin d’être en conformité avec l’acquis communautaire. Le présent chapitre analyse l’Aide Publique au Développement (APD) roumaine afin de mettre en lumière la manière dont l’État incorpore (ou non) cette dernière dans sa politique étrangère. L'auteur réalise une étude de cas sur la mobilisation de l’aide au développement par l’Etat dans sa stratégie d’affirmation comme acteur clé dans la région de la mer Noire, pour la période 2007-2012. Selon l’auteur, l’APD est marginale au sein de la politique étrangère roumaine. Ce manque d’intérêt politique est explicable par la crise économique qui a frappé la Roumanie, un pays qui se relevait seulement des conséquences de la « transition ». Néanmoins, d’autres éléments rentrent également en jeu. Au vu des enjeux géopolitiques de la région, le Ministère des Affaires Étrangères (MAE) conçoit les relations avec les pays riverains de la mer Noire d’abord sous l’angle sécuritaire. La perspective du développement (au sens de lutte contre la pauvreté) est minoritaire. Quatre facteurs institutionnels liés au MAE sont également problématiques : une instabilité politique qui a conduit neuf Ministres différents à la tête du MAE depuis 2007 ; la rotation des diplomates qui nuit à la consolidation d’une mémoire institutionnelle ; le nombre plus réduit d’occasions de socialisation avec le monde du développement par rapport aux ONG ; et enfin la faible attractivité du secteur pour une carrière diplomatique. L’auteur base sa démonstration sur l’analyse de documents officiels roumains et européens liés à la thématique ainsi que sur des sources de première main (entretiens et observation participante). [less ▲]

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See detailConnexion implants - prothèse
Van Heusden, Alain ULg

Conference (2005)

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See detailConnivences d’acteurs, contrats, coopération interentreprises et métamorphose des organisations
Froehlicher, Thomas ULg; Vendemini, Serge

Book published by Presses Universitaires de Nancy (1999)

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See detailLa connotation chez Hjelmslev
Badir, Sémir ULg

in Bulletin de l'Association française de sémiotique (2003), 3

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See detailConodontes, Spores et Foraminifères du Tournaisien Inferieur dans la Vallée du Hoyoux.
Austin, R; Conil, R; Rhodes, F et al

in Annales de la Société Géologique de Belgique (1970), 93(2), 305-315

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See detail"Conquest of Surfaces": Aesthetic and Political Violence in the Work of Janet Frame
Delrez, Marc ULg

in Cronin, Jan; Drichel, Simone (Eds.) Frameworks: Contemporary Criticism on Janet Frame (2009)

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See detailConrad Botes
Meesters, Gert ULg

in De Brakke Hond (2006), (92), 81-82

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See detailConrad Detrez
Hick, Anne-Laure ULg

in Mathis-Moser, Ursula; Mertz-Baumgartner, Birgitt (Eds.) Passages et ancrages en France, Dictionnaire des écrivains migrants de langue française (1981-2011) (2012)

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See detailConrad Detrez
Sindaco, Sarah ULg

in Blanchaud, Corinne (Ed.) Dictionnaire littéraire de cent écrivains francophones classiques. XIXe-XXe siècles. Belgique, Canada, Luxembourg, Suisse (2013)

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See detailConrad's Kurtz in Heart of Darkness and Phillips's Nash in Crossing the River: A Discursive Approach
Najar, Imen ULg

in Gyssels, Kathleen; Ledent, Bénédicte (Eds.) Présence africaine en Europe et au-delà / African Presence in Europe and Beyond (2010)

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See detailConscience de soi dans le vieillissement normal et pathologique
Feyers, Dorothée ULg

Doctoral thesis (2011)

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