RT Journal Article SR Electronic T1 Learned adaptive multiphoton illumination microscopy JF bioRxiv FD Cold Spring Harbor Laboratory SP 2020.08.14.251314 DO 10.1101/2020.08.14.251314 A1 Henry Pinkard A1 Hratch Baghdassarian A1 Adriana Mujal A1 Ed Roberts A1 Kenneth H. Hu A1 Daniel Haim Friedman A1 Ivana Malenica A1 Taylor Shagam A1 Adam Fries A1 Kaitlin Corbin A1 Matthew F. Krummel A1 Laura Waller YR 2020 UL http://biorxiv.org/content/early/2020/08/15/2020.08.14.251314.abstract AB Multiphoton microscopy is a powerful technique for deep in vivo imaging in scattering samples. However, it requires precise, sample-dependent increases in excitation power with depth in order to maintain signal while minimizing photodamage. We show that cells with identical fluorescent labels imaged in situ can be used to train a physics-based machine learning model that solves this problem. After this training has been performed, the correct illumination power can be predicted and adaptively adjusted at each point in a 3D volume on subsequent samples as a function of the sample’s shape, without the need for specialized fluorescent labelling. We use this technique for in vivo imaging of immune responses in mouse lymph nodes following vaccination, with imaging volumes 2-3 orders of magnitude larger than previously reported. We achieve visualization of physiologically realistic numbers of antigen-specific T cells for the first time, and demonstrate changes in the global organization and motility of dendritic cell networks during the early stages of the immune response.Competing Interest StatementThe authors have declared no competing interest.