Recently, the presence of very precise intra-burst firing patterns, which have been named neural signatures, has been reported in bursting neurons of the pyloric network of the lobster stomatogastric nervous system [A. Szucs, R.D. Pinto, M.I. Rabinovich, H.D.I. Abarbanel, A.I. Selverston, Synaptic modulation of the interspike interval signatures of bursting pyloric neurons, J. Neurophysiol. 89, (2003) 1363-1377]. This finding suggests that intra-burst activity may be essential in neural transmission. Typical analysis of intra-burst activity uses the first spike in the burst as the time reference, and computes ISI distributions and return maps to characterize the signatures. In this paper we show that the first spike may not be the best time reference, and propose a new method to align the bursts that minimizes the overlap among the firing time distributions of the different spikes in the burst. The method can be applied to real recordings in order to obtain a better characterization of intra-burst activity.