This it the readme for the MadSim model associated with the paper: Stein W, Straub O, Ausborn J, Mader W, Wolf H. (2008) Motor pattern selection by combinatorial code of interneuronal pathways. J Comput Neurosci 25:543-61 Abstract/Info: We studied the femur-tibia joint control system of the insect leg, and its switch between resistance reflex in posture control and "active reaction" in walking. The "active reaction" is basically a reversal of the resistance reflex. Both responses are elicited by the same sensory input and the same neuronal network (the femur-tibia network). The femur-tibia network was modeled by fitting the responses of model neurons to those obtained in animals. Each implemented neuron has a physiological counterpart. The strengths of 16 interneuronal pathways that integrate sensory input were then assigned three different values and varied independently, generating a database of more than 43 million network variants. The uploaded version contains the model that best represented the resistance reflex. Please see below for more help. We demonstrate that the combinatorial code of interneuronal pathways determines motor output. A switch between different behaviors such as standing to walking can thus be achieved by altering the strengths of selected sensory integration pathways. Short info on using madSim Simulator: Copy the whole madsim folder to your hard disk. No installation needed. Madsim files are called .gui files. They are ASCII text files containing all parameters of the simulation. Click file -> open to open .gui files or use right mouse click to make new neuron / edit properties etc. To display result window in madSim, either select neurons with mouse and press CTRL + M or right click on neuron and select "display diagram window". Then press F1 to start simulation. Please note that madSim was originally developed in German. The English version has the same capablilities, but may come with translation errors. Btw: MadSim uses HH equations and exponential Euler to calculate ion / synaptic currents. Information about the code: Neurons in "stick_insect_FT-simulation_resistance-reflex.gui": Sensory neurons in the femoral chordotonal organ: 1, 10, 11 = position (+) sensitive 30,31,32 = position (-) sensitive 2,3,5,26,27 = velocity (+) sensitive 8,9,12,28,29 = velocity (+) sensitive 20,21,22 = velocity (+) sensitive spiking interneurons 23,24,25 = velocity (-) sensitive spiking interneurons E1 – E10 = identified excitatory nonspiking interneurons I1 – I8 = identified inhibitory nonspiking interneurons IE1 = identified interneuron that inhibits and excites SETi = Slow extensor tibiae motor neuron The model files were supplied by Wolfgang Stein.