Spinal Cord Neuronal Network Simulator

A motoneuron pool in the spinal cord, associated with a given muscle, receives a multitude of neural commands from different parts of the central and peripheral nervous systems. The time course of the firing patterns of the motoneurons will define the dynamic behavior of the innervated muscle. The transformation of all synaptic inputs to the motoneuron pool onto muscle commands depends strongly on each motoneuron’s intrinsic characteristics as well as on the associated neuronal network. As all involved relations are nonlinear, the functioning of the network has to be studied by simulation experiments. In a first stage, as described in this paper, our objective was to build a user-friendly simulator of a spinal cord neuronal network including a motoneuron pool, synaptic inputs from several sources (including the negative feedback due to Renshaw cells) and the generation of force by the associated muscle. There have been efforts described in the literature towards the development of spinal cord simulators (Maltenfort et al. 1998; Uchiyama et al. 2003), but usually the network simulator has been developed to answer a specific question and its general usability by a wider audience (without the need for programming) was not emphasized. In what follows we shall describe the structure of the neuronal network, the basic models employed for each element and the types of graphical analyses included in the simulator.