The lab is located at the Douglas Mental Health University Institute, a research center part of McGill University in Montreal. The lab has evolved significantly since the labs inception from in vitro approaches aiming to better understanding individual neuronal function and local circuits to in vivo experiments aiming to understand how large neuronal populations code for different aspects of memory. At the beginning, we used brain slices to identify and differentiate neuronal populations of the hippocampus and the medial septum, two brain regions critical for learning and memory. For example, we initially discoveredin the medial septum a new population of neurons using glutamate as a transmitter(Sotty et al., 2003). These neurons were also shown to send projections to many different brain areas including the hippocampus. Later on, we developed the isolated hippocampus preparation and the isolated septo-hippocampus preparation (Goutagny et al., 2009). These preparations were extremely valuable because it offered a unique opportunity to determine the interactions of GABAergic interneurons and principal cells during intrinsically-generated oscillatory activity such as theta and gamma rhythms (Amilhon et al., 2015). In the last 5 years, the laboratory has now concentrated all its efforts ininvestigating how identified neurons of the septum and hippocampus code for memory in vivo. In addition to revealing the identity and activity patterns of neurons in the hippocampus and septum using calcium imaging recorded with ‘miniscopes’ in combination to optogenetics and electrophysiology in freely moving mice performing memory tasks, we also investigate the role of these neurons in sleep (Boyce et al., 2016). The overarching goal is to understand the neuronal mechanisms underlying normal memory function in normal and in pathological conditions such as Alzheimer’s disease inmice models.