The main purpose of this paper is to describe several software tools specifically adapted to characterize the electrophysiological behavior of a population of neurons coupled to a planar array of microtransducers by analyzing the recorded signals. Both graphic and signal processing tools are considered. They include: image analysis of the neuronal network topology, peak detection procedure, multi-graphics visualization, spike classification, cross-correlation, interspike and interbursting interval analysis. These tools are utilized to characterize changes induced in the electrophysiological behavior of populations of cultured neurons by modifications to the medium-culture.