RESEARCH ARTICLE Two opposite voltage-dependent currents control the unusual early development pattern of embryonic Renshaw cell electrical activity Juliette Boeri1†, Claude Meunier2†, Herve´ Le Corronc1,3†, Pascal Branchereau4, Yulia Timofeeva5,6, Franc¸ois-Xavier Lejeune7, Christine Mouffle1, Herve´ Arulkandarajah1, Jean Marie Mangin1, Pascal Legendre1‡*, Antonny Czarnecki1,4‡* 1INSERM, UMR_S 1130, CNRS, UMR 8246, Neuroscience Paris Seine, Institute of Biology Paris Seine, Sorbonne Univ, Paris, France; 2Centre de Neurosciences Inte´gratives et Cognition, CNRS UMR 8002, Institut Neurosciences et Cognition, Universite´ de Paris, Paris, France; 3Univ Angers, Angers, France; 4Univ. Bordeaux, CNRS, EPHE, INCIA, Bordeaux, France; 5Department of Computer Science and Centre for Complexity Science, University of Warwick, Coventry, United Kingdom; 6Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, University College London, London, United Kingdom; 7Institut du Cerveau et de la Moelle Epinie`re, Centre de Recherche CHU Pitie´-Salpe´trie`re, INSERM, U975, CNRS, UMR 7225, Sorbonne Univ, Paris, France *For correspondence:
[email protected] (PL);
[email protected] (AC) Abstract Renshaw cells (V1R) are excitable as soon as they reach their final location next to the †These authors contributed spinal motoneurons and are functionally heterogeneous. Using multiple experimental approaches, equally to this work in combination with biophysical modeling and dynamical systems theory, we analyzed, for the first ‡ These authors also contributed time, the mechanisms underlying the electrophysiological properties of V1R during early embryonic equally to this work development of the mouse spinal cord locomotor networks (E11.5–E16.5). We found that these Competing interests: The interneurons are subdivided into several functional clusters from E11.5 and then display an authors declare that no unexpected transitory involution process during which they lose their ability to sustain tonic firing.