International audienceNeo is a hierarchical data model for the representation of intracellular and extracellular electrophysiology data with support for multi-electrodes (for example tetrodes) and EEG data.The Neo project distributes an implementation of this model with a set of input/output (IO) modules for various file formats, as an open-source, multi-platform Python package under a BSD license. It is available at http://pypi.python.org/pypi/neo.The objective of Neo is to facilitate the cooperation between independent software projects working on simulation, modeling, representation and analysis of electrophysiological signals in electroencephalography or intracellular and extracellular electrophysiology.For this, Neo provides a common representation of the core data in order to improve the reusability of the developed tools and share data between different projects. It also provides a common layer for datafile and database reading and writing through its IO modules