Brain lateralization probed by water diffusion at atomic-to-micrometric scale

Combined neutron scattering and diffusion nuclear magnetic resonance experiments have been used to reveal significant interregional asymmetries (lateralization) in bovine brain hemispheres in terms of myelin arrangement and water dynamics at micron to atomic scales. Thicker myelin sheaths were found in the left hemisphere using neutron diffraction. 4.7\u2009T dMRI and quasi-elastic neutron experiments highlighted significant differences in the properties of water dynamics in the two hemispheres. The results were interpreted in terms of hemisphere-dependent cellular composition (number of neurons, cell distribution, etc.) as well as specificity of neurological functions (such as preferential networking)

Divagation violente ? Dans La fille de Christophe Colomb de Réjean Ducharme

CONSIDÉRATIONS GÉNÉRALES Puisque la divagation est essentiellement définie par son manque par rapport à une norme, elle se trouve dépendante de cette norme et liée à elle de façon péjorative. Sans norme, pas de divagation possible. La divagation contient en elle cette norme qui la définit et, du même coup, l’interdit de divagation, implicite ou explicite, qui va de pair avec la perception péjorative de la divagation, se trouve incrusté dans cette divagation, en est une composante fondamentale..

Le jardin des hélices.

Le Jardin des helices est le texte duquel Jerome Bosch a plagie par anticipation la structure pour effectuer le triptyque Le Jardin des helices. La demarche s'impregne de l'esprit pataphysicien, "science des solutions imaginaires" (Alfred Jarry), et tout specialement de l'Oulipo (Ouvroir de litterature potentielle). Le recit offre la mise en pratique d'une contrainte elaboree a partir de reflexions sur le plagiat par anticipation et sur les composantes du tableau de Jerome Bosch, tout specialement les plans et les lignes. La notion de plagiat par anticipation lancee par l'Oulipo se trouve enrichie d'une application ainsi que d'une reflexion sur le processus complexe qu'elle engendre

Water Dynamics in Neural Tissue

Water dynamics in post-mortem two-years old bovine cerebral right hemisphere has been investigated through Elastic and Quasi-elastic Neutron Scattering. Experimental parameters such as stability in time of the proton dynamics, data reproducibility and changes in the tissues dynamics upon the conservation protocol, cryogenic towards formalin addition, have been carefully investigated. Results are extremely encouraging and comparisons to magnetic resonance imaging findings are discussed

Brain lateralization probed by water diffusion at the atomic to micrometric scale

International audienceAbstract Combined neutron scattering and diffusion nuclear magnetic resonance experiments have been used to reveal significant interregional asymmetries (lateralization) in bovine brain hemispheres in terms of myelin arrangement and water dynamics at micron to atomic scales. Thicker myelin sheaths were found in the left hemisphere using neutron diffraction. 4.7 T d MRI and quasi-elastic neutron experiments highlighted significant differences in the properties of water dynamics in the two hemispheres. The results were interpreted in terms of hemisphere-dependent cellular composition (number of neurons, cell distribution, etc.) as well as specificity of neurological functions (such as preferential networking)

Anomalous water dynamics in brain: A combined diffusion magnetic resonance imaging and neutron scattering investigation

Water diffusion is an optimal tool for investigating the architecture of brain tissue on which modern medical diagnostic imaging techniques rely. However, intrinsic tissue heterogeneity causes systematic deviations from pure free-water diffusion behaviour. To date, numerous theoretical and empirical approaches have been proposed to explain the non-Gaussian profile of this process. The aim of this work is to shed light on the physics piloting water diffusion in brain tissue at the micrometre-to-atomic scale. Combined diffusion magnetic resonance imaging and first pioneering neutron scattering experiments on bovine brain tissue have been performed in order to probe diffusion distances up to macromolecular separation. The coexistence of free-like and confined water populations in brain tissue extracted from a bovine right hemisphere has been revealed at the micrometre and atomic scale. The results are relevant for improving the modelling of the physics driving intra- and extracellular water diffusion in brain, with evident benefit for the diffusion magnetic resonance imaging technique, nowadays widely used to diagnose, at the micrometre scale, brain diseases such as ischemia and tumours

Anomalous water dynamics in brain: a combined diffusion magnetic resonance imaging and neutron scattering investigation

International audienceWater diffusion is an optimal tool for investigating the architecture of brain tissue on which modern medical diagnostic imaging techniques rely. However, intrinsic tissue heterogeneity causes systematic deviations from pure free-water diffusion behaviour. To date, numerous theoretical and empirical approaches have been proposed to explain the non-Gaussian profile of this process. The aim of this work is to shed light on the physics piloting water diffusion in brain tissue at the micrometre-to-atomic scale. Combined diffusion magnetic resonance imaging and first pioneering neutron scattering experiments on bovine brain tissue have been performed in order to probe diffusion distances up to macromolecular separation. The coexistence of free-like and confined water populations in brain tissue extracted from a bovine right hemisphere has been revealed at the micrometre and atomic scale. The results are relevant for improving the modelling of the physics driving intra- and extracellular water diffusion in brain, with evident benefit for the diffusion magnetic resonance imaging technique, nowadays widely used to diagnose, at the micrometre scale, brain diseases such as ischemia and tumours