Researchers have demonstrated a noninvasive approach for creating an optical window in the skulls of mice to image their brains. Prof. Dan Zhu and coworkers from Huazhong University of Science and Technology, China, tested the use of optical clearing agents (OCAs) that they applied to the bare skulls (hair and skin removed) of living mice. After treatment with OCAs, the skull becomes transparent within minutes, thus forming a visible window into the cortex. Combined with two-photon microscopy, this technique allows imaging of the fine structures of neurons, glia and the microvasculature in the mouse brain. Given its easy handling, safety, repeatability and excellent performance, this method has promise in neuroscience research. The research has been published in journal Light: Science and Applications.