A model of the leech segmental swim central pattern generator

We present a model of the single-ganglion oscillator of the leech swim cent ral pattern generator (CPG). The model is based on the known neuronal archi tecture of this circuit. Free parameters in the model were fitted to produc e membrane potential oscillations matching those seen during swimming. Howe ver, the oscillations produced are not robust to small (+/- 5%) changes in the parameters. We propose that this may be due to the large difference bet ween the passive time constant of our model cells and the period of the swi m oscillation. We discuss possible ways the real circuit achieves robustnes s. (C) 2000 Elsevier Science B.V. All rights reserved.