Neural Substrates of Transcutaneous Spinal Cord Stimulation: Neuromodulation across Multiple Segments of the Spinal Cord

Transcutaneous spinal cord stimulation (tSCS) has the potential to promote improved sensorimotor rehabilitation by modulating the circuitry of the spinal cord non-invasively. Little is currently known about how cervical or lumbar tSCS influences the excitability of spinal and corticospinal networks, or whether the synergistic effects of multi-segmental tSCS occur between remote segments of the spinal cord. The aim of this review is to describe the emergence and development of tSCS as a novel method to modulate the spinal cord, while highlighting the effectiveness of tSCS in improving sensorimotor recovery after spinal cord injury. This review underscores the ability of single-site tSCS to alter excitability across multiple segments of the spinal cord, while multiple sites of tSCS converge to facilitate spinal reflex and corticospinal networks. Finally, the potential and current limitations for engaging cervical and lumbar spinal cord networks through tSCS to enhance the effectiveness of rehabilitation interventions are discussed. Further mechanistic work is needed in order to optimize targeted rehabilitation strategies and improve clinical outcomes

DC MicroGrids

International audienceThis chapter introduces concepts of DC MicroGrids exposing their elements, features, modeling, control, and applications. Renewable energy sources, energy storage systems, and loads are the basics components of a DC MicroGrid. These components can be better integrated thanks to their DC feature, resulting in simpler power converter topologies, as well as the control strategy required for this application. A DC MicroGrid is developed as a realistic average model where the dynamics of the system are expressed in differential equations, including the nonlinearities of the model. A nonlinear distributed control strategy is developed for the DC MicroGrid, assuring the stability of the DC bus to guarantee the proper operation of each component of the MicroGrid. The energy storage systems are separated according to their timescale operation, where a faster one (supercapacitor) controls voltage variations on the DC bus, and a slower one (battery) provides the power flow balance. The comparison with classical linear controllers is carried out to highlight the better performance of the nonlinear approach