34 research outputs found
Biological Principles in Self-Organization of Young Brain - Viewed from Kohonen Model
Get PDFVariants of the Kohonen model are proposed to study biological principles of
self-organization in a model of young brain. We suggest a function to measure
aquired knowledge and use it to auto-adapt the topology of neuronal
connectivity, yielding substantial organizational improvement relative to the
standard model. In the early phase of organization with most intense learning,
we observe that neural connectivity is of Small World type, which is very
efficient to organize neurons in response to stimuli. In analogy to human brain
where pruning of neural connectivity (and neuron cell death) occurs in early
life, this feature is present also in our model, which is found to stabilize
neuronal response to stimuli
Vascular and blood-brain barrier-related changes underlie stress responses and resilience in female mice and depression in human tissue
Get PDFPrevalence, symptoms, and treatment of depression suggest that major depressive disorders (MDD) present sex differences. Social stress-induced neurovascular pathology is associated with depressive symptoms in male mice; however, this association is unclear in females. Here, we report that chronic social and subchronic variable stress promotes blood-brain barrier (BBB) alterations in mood-related brain regions of female mice. Targeted disruption of the BBB in the female prefrontal cortex (PFC) induces anxiety- and depression-like behaviours. By comparing the endothelium cell-specific transcriptomic profiling of the mouse male and female PFC, we identify several pathways and genes involved in maladaptive stress responses and resilience to stress. Furthermore, we confirm that the BBB in the PFC of stressed female mice is leaky. Then, we identify circulating vascular biomarkers of chronic stress, such as soluble E-selectin. Similar changes in circulating soluble E-selectin, BBB gene expression and morphology can be found in blood serum and postmortem brain samples from women diagnosed with MDD. Altogether, we propose that BBB dysfunction plays an important role in modulating stress responses in female mice and possibly MDD
Ethique et environnement à l'aube du 21ème siècle : la crise écologique implique-t-elle une nouvelle éthique environnementale ?
No full textL’éthique de l’environnement, entendue comme champ de discussion multidisciplinaire, ouvre sur l’élaboration tant d’interventions spécifiques fondées sur des choix de valeurs, que sur des réflexions normatives élargies pour la société et les décideurs. Dans un contexte marqué par le changement climatique, par des dégradations majeures affectant les milieux naturels (érosion, pertes de biodiversité, pollutions…) ou encore par la raréfaction de ressources inégalement réparties dans l’espace (re..
