TY - JOUR T1 - Volumetric Calcium Imaging of 1 Million Neurons Across Cortical Regions at Cellular Resolution using Light Beads Microscopy JF - bioRxiv DO - 10.1101/2021.02.21.432164 SP - 2021.02.21.432164 AU - Jeffrey Demas AU - Jason Manley AU - Frank Tejera AU - Hyewon Kim AU - Kevin Barber AU - Francisca Martínez Traub AU - Brandon Chen AU - Alipasha Vaziri Y1 - 2021/01/01 UR - http://biorxiv.org/content/early/2021/02/22/2021.02.21.432164.abstract N2 - Two-photon microscopy together with genetically encodable calcium indicators has emerged as a standard tool for high-resolution imaging of neuroactivity in scattering brain tissue. However, its various realizations have not overcome the inherent tradeoffs between speed and spatiotemporal sampling in a principled manner which would be necessary to enable, amongst other applications, mesoscale volumetric recording of neuroactivity at cellular resolution and speed compatible with resolving calcium transients. Here, we introduce Light Beads Microscopy (LBM), a scalable and spatiotemporally optimal acquisition approach limited only by fluorescence life-time, where a set of axially-separated and temporally- distinct foci record the entire axial imaging range near-simultaneously, enabling volumetric recording at 1.41 × 108 voxels per second. Using LBM, we demonstrate mesoscopic and volumetric imaging at multiple scales in the mouse cortex, including cellular resolution recordings within ∼3×5×0.5 mm3 volumes containing >200,000 neurons at ∼5 Hz, recording of populations of ∼1 million neurons within ∼5.4×6×0.5 mm3 volumes at ∼2 Hz as well as higher-speed (9.6 Hz) sub-cellular resolution volumetric recordings. LBM provides an unprecedented opportunity for discovering the neurocomputations underlying cortex-wide encoding and processing of information in the mammalian brain.Competing Interest StatementThe authors have declared no competing interest. ER -