Research topic

Our laboratory studies the neuronal networks that are responsible for the generation of the state of sleep and wakefulness. It does so by using a multidisciplinary approach that ranges from the molecular and cellular levels to a more integrated circuit level. We have thus studied in the past the GABAergic sleep-promoting neurons of the preoptic area and more recently the hypocretin/orexin wake-promoting neurons of the lateral hypothalamus. The interest in this latter system stems from the discovery that it is the only one whose alteration leads to the sleep/wake disorder narcolepsy. After having studied the properties of the hypocretin/orexin neurons themselves and the actions of their peptidergic transmitter, hypocretin/orexin, on the major systems of arousal and the thalamo-cortical system, we have become interested in the actions of hypocretin/orexin on the cortical neurons of layer 6b in the mouse as this layer has been shown to provide widespread cortico-cortical projections. We have thus demonstrated that, in the somatosensory cortex, only neurons of that layer are directly sensitive to the peptide. Our present focus is on characterizing the different cell types present in this layer and understanding their direct or indirect modulation by hypocretin/orexin