BlueBerry: Closed-loop wireless optogenetic manipulation in freely moving animals

Optogenetics is a powerful tool for neuroscientists, enabling manipulations of neuronal activity to explore their effects on behavior. Recent advances in wireless technology enabled the development of novel remotely controlled optogenetic devices, thereby promising to facilitate the study of more complex behaviors, including social interactions. Yet, studying such behaviors in real time and automated manner in large scale naturalistic settings or with multiple animals remains challenging. In addition, many published devices can only be reproduced in labs having specific engineering skills and fabrication facilities and are thus not accessible for the larger neuroscience community. Here we introduce BlueBerry, an open-source, multi-channel optogenetic device that can be assembled with off the shelf components. The lightweight (1.4 g) design and robust long-range communication makes Blueberry an ideal tool for behavior-triggered optogenetic studies with multiple animals interacting freely in a large-scale setting. We show how BlueBerry can be used to guide decision making during spatial navigation and demonstrate for the first time that social dynamics can be rapidly altered in groups of mice by triggering specific social behavior with closed-loop optogenetics.