Three-photon neuronal imaging in deep mouse brain

Three-photon microscopy has been increasingly adopted for probing neural activities beyond the typical two-photon imaging depth. In this review, we outline the unique properties that differentiate three-photon microscopy from two-photon microscopy for in vivo imaging in biological samples, especially in the mouse brain. We present a systematic summary of the optimization of three-photon imaging parameters for neural imaging, based on their effects on calcium imaging quality and perturbation to brain tissues. Furthermore, we review the existing techniques for volumetric imag-ing and discuss their prospects in mesoscale three-photon imaging in deep tissue. (C) 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreement p https://doi.org/10.1364/OPTICA.395825