Neuronal networks produce reliable functional output throughout the lifespan of an animal despite ceaseless molecular turnover and a constantly changing environment. Central pattern generators, such as that of the crustacean stomatogastric ganglion (STG), robustly maintain their functionality over a wide range of burst periods [1]. Extracellular recordings of the LP neuron of the STG have demonstrated that as the burst period varies over time, the interspike intervals change proportionally, so that the spike phases are relatively invariant.