title: Generation of Locomotor-Like Activity in the Isolated Rat Spinal Cord Using Intraspinal Electrical Microstimulation Driven by a Digital Neuromorphic CPG.
abstract: Neural prostheses based on electrical microstimulation offer promising perspectives to restore functions following lesions of the central nervous system (CNS). They require the identification of appropriate stimulation sites and the coordination of their activation to achieve the restoration of functional activity. On the long term, a challenging perspective is to control microstimulation by artificial neural networks hybridized to the living tissue. Regarding the use of this strategy to restore locomotor activity in the spinal cord, to date, there has been no proof of principle of such hybrid approach driving intraspinal microstimulation (ISMS). Here, we address a first step toward this goal in the neonatal rat spinal cord isolated ex vivo, which can display locomotor-like activity while offering an easy access to intraspinal circuitry. Microelectrode arrays were inserted in the lumbar region to determine appropriate stimulation sites to elicit elementary bursting patterns on bilateral L2/L5 ventral roots. Two intraspinal sites were identified at L1 level, one on each side of the spinal cord laterally from the midline and approximately at a median position dorso-ventrally. An artificial CPG implemented on digital integrated circuit (FPGA) was built to generate alternating activity and was hybridized to the living spinal cord to drive electrical microstimulation on these two identified sites. Using this strategy, sustained left-right and flexor-extensor alternating activity on bilateral L2/L5 ventral roots could be generated in either whole or thoracically transected spinal cords. These results are a first step toward hybrid artificial/biological solutions based on electrical microstimulation for the restoration of lost function in the injured CNS.
authors.affiliation: Centre National de la Recherche Scientifique, Institute for Cognitive and Integrative Neuroscience (INCIA), UMR 5287Talence, France; Institute for Cognitive and Integrative Neuroscience (INCIA), UMR 5287, University of BordeauxTalence, France.
authors.forename: Sébastien
authors.initials: S
authors.lastname: Joucla
authors.affiliation: Laboratoire de l'Intégration du Matériau au Système, UMR 5218, University of BordeauxTalence, France; Centre National de la Recherche Scientifique, Laboratoire de l'Intégration du Matériau au Système, UMR 5218Talence, France.
authors.forename: Matthieu
authors.initials: M
authors.lastname: Ambroise
authors.affiliation: Laboratoire de l'Intégration du Matériau au Système, UMR 5218, University of BordeauxTalence, France; Centre National de la Recherche Scientifique, Laboratoire de l'Intégration du Matériau au Système, UMR 5218Talence, France.
authors.forename: Timothée
authors.initials: T
authors.lastname: Levi
authors.affiliation: Centre National de la Recherche Scientifique, Institute for Cognitive and Integrative Neuroscience (INCIA), UMR 5287Talence, France; Institute for Cognitive and Integrative Neuroscience (INCIA), UMR 5287, University of BordeauxTalence, France.
authors.forename: Thierry
authors.initials: T
authors.lastname: Lafon
authors.affiliation: Centre National de la Recherche Scientifique, Institute for Cognitive and Integrative Neuroscience (INCIA), UMR 5287Talence, France; Institute for Cognitive and Integrative Neuroscience (INCIA), UMR 5287, University of BordeauxTalence, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Chauvet
authors.affiliation: Laboratoire de l'Intégration du Matériau au Système, UMR 5218, University of BordeauxTalence, France; Centre National de la Recherche Scientifique, Laboratoire de l'Intégration du Matériau au Système, UMR 5218Talence, France.
authors.forename: Sylvain
authors.initials: S
authors.lastname: Saïghi
authors.affiliation: Laboratoire de l'Intégration du Matériau au Système, UMR 5218, University of BordeauxTalence, France; Bordeaux INP, Laboratoire de l'Intégration du Matériau au Système, UMR 5218Talence, France.
authors.forename: Yannick
authors.initials: Y
authors.lastname: Bornat
authors.affiliation: Laboratoire de l'Intégration du Matériau au Système, UMR 5218, University of BordeauxTalence, France; Centre National de la Recherche Scientifique, Laboratoire de l'Intégration du Matériau au Système, UMR 5218Talence, France.
authors.forename: Noëlle
authors.initials: N
authors.lastname: Lewis
authors.affiliation: Laboratoire de l'Intégration du Matériau au Système, UMR 5218, University of BordeauxTalence, France; Bordeaux INP, Laboratoire de l'Intégration du Matériau au Système, UMR 5218Talence, France.
authors.forename: Sylvie
authors.initials: S
authors.lastname: Renaud
authors.affiliation: Centre National de la Recherche Scientifique, Institute for Cognitive and Integrative Neuroscience (INCIA), UMR 5287Talence, France; Institute for Cognitive and Integrative Neuroscience (INCIA), UMR 5287, University of BordeauxTalence, France; Institut National de la Santé et de la Recherche Médicale, Clinatec-Lab, U1205Grenoble, France; Université Grenoble Alpes, Clinatec-Lab, U1205Grenoble, France.
authors.forename: Blaise
authors.initials: B
authors.lastname: Yvert
keywords: hybrid neural networks; neural prostheses; neuromorphic hardware; rehabilitation