RT Journal Article SR Electronic T1 Mesoscopic oblique plane microscopy (Meso-OPM) - enabling large-scale 4D isotropic cellular resolution imaging with a diffractive light sheet JF bioRxiv FD Cold Spring Harbor Laboratory SP 2022.03.29.486239 DO 10.1101/2022.03.29.486239 A1 Wenjun Shao A1 Minzi Chang A1 Kevin Emmerich A1 Patrick O Kanold A1 Jeff S Mumm A1 Ji Yi YR 2022 UL http://biorxiv.org/content/early/2022/03/30/2022.03.29.486239.abstract AB Fundamental understanding of large-scale dynamic connectivity within a living organism requires volumetric imaging over a large field of view (FOV) at biologically relevant speed and resolution. However, most microscopy methods make trade-offs between FOV and resolution or imaging speed, making it challenging to observe highly dynamic processes at cellular resolution across mesoscopic scales (e.g., whole zebrafish larva). To overcome this limitation, we have developed mesoscopic oblique plane microscopy (Meso-OPM) with a diffractive light sheet. By augmenting the illumination angle of the light sheet with a transmission grating, the axial resolution was improved ~7-fold over existing methods and ~2-fold beyond the diffraction limitation of the primary objective lens. We demonstrated an unprecedented FOV up to 5.4 × 3.3 mm with resolution of 2.5× 3 × 6 μm, allowing volumetric imaging of cellular structures in an uncleared brain slice with a single scan. Applying Meso-OPM for in vivo imaging of zebrafish larvae, we report here the first whole fish volumetric recordings of neuronal activity at 2 Hz volume rate and the first example of whole fish volumetric recordings of blood flow dynamics at 5 Hz with isotropic cellular resolution.Competing Interest StatementThe authors have declared no competing interest.