Analysis of the activation of spinal nerves during magnetic stimulation of the lumbar area

This paper aims in estimating which nerve fibers can be activated during magnetic stimulation of the lumbar area of the thorax. For this purpose, we compute the electrical field and the activation function induced in the tissue. We used a simplified model, where the spinal cord is modeled as a continuous cylinder, while the vertebral column is also represented by a concentric interrupted cylinder. The general thorax is also modeled as a parallelipipedic domain that includes all these structures. The coil used for magnetic stimulation is a figure of eight, whose center is placed above L1-L2 vertebras.