A head-mounted open-source light field microscope for large volumetric Ca(2+) imaging during exploratory and social behavior in mice.

MiniLFMv2 enables high-resolution, large-volume, deep neuronal imaging at 30 Hz in freely moving mice, capturing activity from hundreds of parietal cortex neurons.

• Why it matters: Understanding brain function during natural behaviors requires imaging systems that combine volumetric coverage, resolution, and usability in unrestrained animals, a current technological challenge.
• What they did: The team developed MiniLFMv2, a lightweight, open-source, head-mounted light field microscope with a 1 × 0.2 mm³ volume of interest, 350–400 μm depth, and near-diffraction-limited performance, using custom lenses and an electrically tunable lens.
• The result: This system successfully recorded neural activity during naturalistic behaviors, revealing subpopulations tuned to locomotion, rearing, and social investigation, thus enabling detailed studies of neural dynamics in freely behaving animals.