Advanced optical imaging techniques for neurodevelopment

•We describe recent advances in optical imaging of neurodevelopment.•Advances in multiphoton microscopy provide increased imaging depth and speed for investigation of neuronal activity in 3D.•Super-resolution imaging offers resolution down to tens of nm, revealing fine structures in the nervous system.•Light sheet microscopy permits long-term, in toto observation of embryogenesis.•Intrinsic contrast imaging allows direct visualization of neuroanatomy.

Over the past decade, developmental neuroscience has been transformed by the widespread application of confocal and two-photon fluorescence microscopy. Even greater progress is imminent, as recent innovations in microscopy now enable imaging with increased depth, speed, and spatial resolution; reduced phototoxicity; and in some cases without external fluorescent probes. We discuss these new techniques and emphasize their dramatic impact on neurobiology, including the ability to image neurons at depths exceeding 1 mm, to observe neurodevelopment noninvasively throughout embryogenesis, and to visualize neuronal processes or structures that were previously too small or too difficult to target with conventional microscopy.