Multiphoton microscopy is the current method of choice for in vivo deep-tissue imaging. The long laser wavelength suffers less scattering, and the 3D-confined excitation permits the use of scattered signal light. However, the imaging depth is still limited because of the complex refractive index distribution of biological tissue, which scrambles the incident light and destroys the optical focus needed for high resolution imaging. Here, we demonstrate a wavefrontshaping scheme that allows clear imaging through extremely turbid biological tissue, such as the skull, over an extended corrected field of view (FOV). The complex wavefront correction is obtained and directly conjugated to the turbid layer in a noninvasive manner. Using this technique, we demonstrate in vivo submicron-resolution imaging of neural dendrites and microglia dynamics through the intact skulls of adult mice. This is the first observation, to our knowledge, of dynamic morphological changes of microglia through the intact skull, allowing truly noninvasive studies of microglial immune activities free from external perturbations.neuroimaging | nonlinear microscopy | wavefront shaping | immunology | adaptive optics B reakthroughs in imaging technologies have been one of the major driving forces of new discoveries in biology (1). In the past two decades, we have witnessed that the advances of superresolution microscopy revolutionized our understanding of the complex dynamics in single cells (2). However, the techniques that work well on cultured cells often fail when being used to observe the cells in their native environment inside a living organism, the most ideal condition for biological studies. These difficulties result from the optical wavefront distortions induced by the inhomogeneous refractive index distribution in biological tissue.Because of this limitation, imaging inside deep tissue has been a challenging task, and the common goal of state of the art deep tissue-imaging methods is to recover the diffraction-limited resolution. These efforts can be categorized largely into two groups: the first capitalizes the use of longer wavelengths (3, 4) that undergo less scattering, whereas the second controls the optical wavefront, so that the wavefront distortions induced by the sample can be compensated (5-30). Longer wavelength excitation has demonstrated impressive penetration depths in the exposed brain (3) and imaging of the brain vascular structures beneath the skull (4). However, at the current state, using longer wavelengths is not a simple option because it requires special illumination sources [e.g., low repetition rate, high energy pulses (3)] or fluorescent probes (4), and provides only moderate spatial resolutions. In comparison, wavefront shaping allows the use of conventional light sources as well as the wide selection of wellestablished labels and functional indicators (31).Previous exciting works in adaptive optics (AO) have exploited these advantages and demonstrated aberration correction for a large field of view (FOV) by avera...