Chronic Two-Photon Imaging of Neural Activity in the Anesthetized and Awake Behaving Rodent

Chronic in vivo two-photon imaging of genetically encoded sensors has recently enabled the measurement of activity from the same individual neurons repeatedly in different imaging sessions over months, opening new possibilities to investigate the function and plasticity of neuronal activity in both anesthetized and awake animals. A successful chronic imaging experiment involves the combination of several key techniques, including expression of genetically encoded indicators, optical measurement with cellular resolution through a cranial window, and, in awake animals, behavioral paradigms adapted to the two-photon microscope. Here we cover methods and advances in chronic imaging of cortical activity in the awake, behaving rodent for the investigation of learning and performance of sensory and cognitive tasks.