The research aims of Neurobiological Rhythms and Sleep are focused on the molecular, cellular and behavioral mechanisms of the circadian timing system and the consequences of aging and neurodegenerative disease. Our approaches strive to understand the mechanisms of synchronization of circadian rhythms by lignt, the molecular and physiological mechanisms of the endogenous circadian oscillators, and the regulation of output behavioral and physiological rhythms. The coding of photic information by retinal photoreceptors (rods, cones, melanopsin ganglion cells) are studied using in vivo electrophysiological recording techniques in anaesthetised and awake, freely moving animals. The effects of light (intensity, duration, spectrum) on SCN neuronal activity and on clock gene expression are also assayed using quantitative RT-PCR and microarray analysis. In order to understand the consequences of chronobiological disorders, another line of research involves investigation of the mechanisms of synchronisation of central and peripheral oscillators, including the expression of clock genes and rhythmically expressed clock controlled genes in the brain and in different body tissues. Pathological models studied include ocular diseases and Parkinson's disease in rodents and aging in a prosimian primate. In humans, circadian photoreception and entrainment of the circadian timing system as well as chronobiological disorders related to ocular pathologies, aging and neurodegenerative diseases are studied in the framework of a European integrated project EUClock in our clinically based Platform for Research on Human Chronobiology. In order to bridge the gap between cellular-molecular studies in rodent models and clinical studies in humans, the non-human primate is used to study the circadian timing system and sleep wake cycle and, in the framework of the laboratory transverse project, the chronobiological consequences of Parkinson's Disease.