The brain is a powerful organ that regulates health and drives intelligence. How can we see more clearly into the working brain to understand it better? High-resolution optical microscopy has long been an ideal tool due to its spatial sub-micron precision and specificity. However, achieving the necessary spatio-temporal scale for further advancing our understanding of the brain remains a challenge. The primary obstacle originates from the inhomogeneous nature of tissues, which distort light and compromise imaging depth, precision, and information.

In this talk, I will introduce new in vivo deep tissue optical microscopy platforms advanced in microscope design and computational tools, to address existing challenges. By moving towards longer wavelengths for one-, two-, and three-photon microscopy, we have achieved simultaneous deep structural and functional imaging through an entire cortical column with multiple label-free and fluorescence contrasts. With precise control of light, we have enabled adaptive optical imaging of dendritic spines and myelinated axons up to the hippocampus. With a new AI-enabled tool, we have sped up volumetric 3D imaging for microvasculature, neurons, and dendrites. These techniques advance toward imaging the dynamic, cell-type-specific processes and microvasculature within the living brain. I will conclude by discussing the opportunities these enabling optical microscopy techniques offer for biology and clinical applications.