Modulation de la synchronisation corticale par les champs électriques endogènes
Modulation of intercolumnar synchronization by endogenous electric fields in cerebral cortex Neurons interact through signals of electric nature, and it is well known that an external electric field can affect neurons. However, it was never shown wheher endogenous electric fields, generated by the neurons themselves, can influence other neurons. This is what has shown this study which appeared in Science Advances, arising from a collaboration between a laboratory from Barcelona (Mavi Sanchez-Vives) and a research team at the NeuroPSI institute of Paris-Saclay University (Alain Destexhe, UMR 9197 CNRS/UPSaclay, Gif-sur-Yvette). The authors have demonstrated, using in vitro techniques, that cortical slides can synchronize if they are juxtaposed, but if one inverts their orientation, no synchronization occurs. Computational modeling indicates first, that in a cortical « column », neurons are oriented in parallel and form electric dipoles that summate. Second, the electric field produced by a population of neurons can influence another population if they dipoles are oriented in parallel. This study therefore shows that in a large-scale network, the fact that neuronadipoles are oriented in parallel enables neuronal populations to mutually influence one another through electric fields. This electric field effect is a factor that participates to the synchronization at large scales. This interaction is quasi-instantaneous (the electric field propagates at a velocity close to light speed in the medium), which contrasts with synaptic transmission which is much slower. Thus, cortical neurons possess an ultra-fast mechanism which allows them to interact and synchronize.