The long-term goal of the Han Lab is to understand and manipulate learning in the hippocampus, a brain area that is impaired in many neurodegenerative and cognitive disorders such as Alzheimer’s disease. To accomplish this goal we use advanced optical imaging and electrophysiology methods to study neuronal activity in awake, behaving animals. One major line of research in the lab is studying learning-related neuronal activity using two-photon calcium imaging in animals performing a virtual reality behavioral task. This innovative approach allows us to probe neural circuit function from the level of proteins, to networks, to behavior, in real-time. A second major line of research is to apply this methodology to investigate the role of toxic protein aggregates associated with Alzheimer’s disease on neuronal health and function.