The goal of this project is to investigate the dynamic of network interactions in the basal ganglia, a network of subcortical nuclei whose dysfunction in human is associated with Parkinson disease, obsessive-compulsive disorders and addiction. So far, based essentially on anatomical data, the type of computation performed by the basal ganglia has been understood according to two opposite models: (1) a network of independent parallel channels of information processing or a network of interacting and convergent channels. The goal of this project is to test the hypotheses of (in)dependence between channels inside a single basal ganglia nucleus (Aim 1) and to examine the process of information transfer between two connected nuclei (Aim 2). To reach these objectives, large-scale neuronal recording techniques will be used in rats performing an original operant behavioral protocol that include two well specified motor tasks. To achieve Aim 1, micro-machined silicon-based electrodes recordings will be performed along the dorsolateral-ventromedial axis of the striatum when animals perform the operant task. To achieve Aim 2, silicon probe recordings will be performed simultaneously in the striatum and the lateral globus pallidus. Synchrony across and temporal coordination within the activity of distinct sites (local field potential activity and ensembles of single-units) will be used to index interaction and network communication. The recording techniques and analytical tools proposed here are similar to those used during the post-doctoral work of the Principal Investigator and preliminary results have already been obtained. The results obtained will clarify which of the 2 models (parallel vs. interactive channels) is correct and provide new insight on the nature of information flow in the basal ganglia. Such insights will provide new strategy to treat such widespread pathologies as addiction or obsessive-compulsive disorders.