摘要： Neuronal imaging in unrestrained animals has expanded the range of behaviors amenable to circuit-level studies in several model organisms. Advances in imaging technology and in fluorescent sensors have allowed detailed analyses of the neuronal activity underlying a variety of behaviors in animals as diverse as rats, mice, fish, flies and worms. Restraining animals gives experimenters exquisite control over the sensory environment of their subjects, which can be advantageous for studies of visually guided or olfactory-guided behaviors, for example. However, restrained animals are limited in their ability to exhibit more complex behaviors, particularly social behaviors. Technological developments in recent years have made it possible to image neuronal activity in freely behaving animals. For its potential to allow scientists to study the neuronal basis of naturalistic behaviors at the cell, circuit and whole-brain levels, we have chosen imaging in freely behaving animals as Method of the Year 2018.