A HEAD-MOUNTED MINIATURIZED LIGHT-FIELD MICROSCOPE (MINILFMV2) FOR LARGE-SCALE VOLUMETRIC IMAGING OF NEURAL DYNAMICS DURING NATURAL BEHAVIOR

Understanding brain function requires capturing neuronal activity during natural behaviors in unrestrained animals. However, existing imaging systems often fail to combine large volumetric fields-of-view (v-FOV) with high resolution and depth penetration in a usable and affordable head-mounted format. We present the MiniLFMv2, a next-generation lightweight miniaturized light-field microscope that addresses these challenges.
The MiniLFMv2 provides high-speed volumetric imaging with an extended v-FOV of d = 1 mm × 0.2 mm and volume rates up to 30 Hz at tissue depths of up to 350–400 μm. By utilizing custom aspheric optical elements and an electrically tunable lens, the device eliminates the need for gradient index (GRIN) optics, enhancing compatibility with standard cranial windows, but remains optionally compatible with GRIN relays.
We validated the system via in vivo recordings in the parietal cortex of freely moving mice expressing SomaGCaMP7f. The device captured activity from 350–500 active neurons per volume with minimal impact on natural locomotion, rearing, or stationary behavior. Receiver Operating Characteristic (ROC)-based classification revealed distinct and overlapping neuronal subpopulations: approximately 24% of neurons were modulated during locomotion or rearing, while social interaction assays identified specific ensembles tuned to social investigation (9% excited, 6% inhibited) rather than object exploration. These results demonstrate that the MiniLFMv2 is a powerful tool for studying large-scale neural dynamics during complex, naturalistic behaviors.
Funding: National Science Foundation 1707408 (AV), Kavli Foundation, Kavli Neural System Institute (AV), Kavli Foundation, Kavli Neural Systems Institute (TN), National Institutes of Health 1RF1NS110501 (AV), National Institutes of Health 1RF1NS113251 (AV)