'High-resolution structural and functional deep brain imaging using adaptive optics three-photon microscopy' is published in Nature Methods.
Streich et al. (2021) used a deformable mirror and a modal adaptive optics strategy, summing up to 60 Zernike modes, to correct aberrations when imaging in mouse neocortex and hippocampus. As expected, AO-based aberration correction improved resolution and image brightness across a range of imaging depths, with up to a 5-fold increase in image brightness.
Streich et al. (2021) also made a number of valuable observations along the way. Firstly, the only the first ~20 modes contributed to the improvements, the next ~40 modes adding little. Secondly, the isoplanatic patch in brain tissue extends over hundreds of micrometers in the axial dimension, but only tens of micrometers in the transverse dimension, meaning that modal AO is effective across only a small field of view, but that there's little benefit to updating AO when shifting focus over several hundred micrometers.