PT - JOURNAL ARTICLE AU - Shigenori Inagaki AU - Masakazu Agetsuma AU - Shinya Ohara AU - Toshio Iijima AU - Tetsuichi Wazawa AU - Yoshiyuki Arai AU - Takeharu Nagai TI - <em>In vivo</em> brain activity imaging of interactively locomoting mice AID - 10.1101/203422 DP - 2017 Jan 01 TA - bioRxiv PG - 203422 4099 - http://biorxiv.org/content/early/2017/10/15/203422.short 4100 - http://biorxiv.org/content/early/2017/10/15/203422.full AB - Electrophysiological field potential dynamics have been widely used to investigate brain functions and related psychiatric disorders. Conversely, however, various technical limitations of conventional recording methods have limited its applicability to freely moving subjects, especially when they are in a group and socially interacting with each other. Here, we propose a new method to overcome these technical limitations by introducing a bioluminescent voltage indicator called LOTUS-V. Using our simple and fiber-free recording method, named “SNIPA,” we succeeded in capturing brain activity in freely-locomotive mice, without the need for complicated instruments. This novel method further allowed us to simultaneously record from multiple independently-locomotive animals that were interacting with one another. Further, we successfully demonstrated that the primary visual cortex was activated during the interaction. This methodology will further facilitate a wide range of studies in neurobiology and psychiatry.