We investigate the anatomical and functional organization of the basal ganglia, a set of subcortical structures involved in motor behavior, in rodents, human and non-human primates. Our research projects aim at characterizing alterations of neuronal circuits that occur in Parkinson’s disease and Huntington’s chorea using animal models of neurodegenerative diseases and post-mortem human brain. We take advantage of a vast array of methodological approaches that include in vivo electrophysiological recordings followed by tracer injections and three-dimensional reconstructions of neurons, examination of synaptic contacts by electron microscopy, localization of neurotransmitters and analysis of post-mortem human brain tissue using optical and confocal microscopy.