Multi-region two-photon calcium imaging in freely moving animals

MINI2P-II, a 1.1-g two-photon miniscope, enables simultaneous high-resolution calcium imaging in widely separated or adjacent brain regions in freely moving mice and zebra finches.

• Why it matters: Optical tools have not combined multi-region coverage, high spatiotemporal resolution, and freely moving recording, limiting study of distributed neural circuit coordination.
• What they did: The authors built MINI2P-II with dual-color capability and deep imaging, and paired it with a dual-scope system plus an implantable periscope lens assembly for simultaneous two-photon imaging.
• The result: In mice, they demonstrate inter-hemisphere coordination in bilateral motor cortex during climbing and egocentric boundary coding from retrosplenial and posterior parietal cortex; in zebra finches, behavior-dependent activity appears in both juvenile and adult individuals.