"After years of development, researchers have managed to shrink two-photon microscopy into a device that can be mounted on rodents' heads without impeding behaviour."<p>"[The] thumb-sized two-photon fluorescence microscope... can illuminate and record living tissue at depths that are unattainable with conventional fluorescence microscopes. Weighing just 2.4 grams, the Mini2P can be attached to the head of a mouse and track the activity of hundreds, even thousands, of neurons while the animal runs, climbs and leaps from a platform."<p>"The Mini2P achieves 'nearly as good' resolution as a bulky bench-top two-photon system. It is also open-source, with parts lists and instructional videos available on GitHub."<p><a href="https://github.com/kavli-ntnu/MINI2P_toolbox" rel="nofollow">https://github.com/kavli-ntnu/MINI2P_toolbox</a>