Abstract
A major challenge in neuroscience is convenient whole-brain delivery of transgenes, especially early in postnatal development. Recent advances demonstrate whole-brain gene delivery by retro-orbital injection of virus, but slow and sparse expression, and the large injection volumes required, precludes early developmental studies. We developed a novel method for simple, fast and efficient gene delivery across the central nervous system in neonates as early as P4 and persisting into adulthood. The method employs transverse sinus injections of 2-4μL of AAV9 at P0. Here, we describe how to use this method to label and/or genetically manipulate cells in the neonatal rat and mouse brain. This protocol is fast, easy, can be readily adopted by any laboratory, and utilizes the widely available AAV9 capsid. The procedure outlined here is adaptable for diverse experimental applications ranging from biochemistry, anatomical and functional mapping, to gene expression, silencing, and editing.