Adeno-associated viral vectors for anterograde axonal tracing with fluorescent proteins in nontransgenic and cre driver mice.

Harnessing the natural ability of viruses to infect post-mitotic cells such as neurons has provided an explosion of new methods to manipulate and reconstruct neural circuits in vivo. Here we describe the use of recombinant adeno-associated viral vectors (rAAV) for axonal tract tracing in nontransgenic and transgenic Cre driver mice. Two protocols are presented for stereotactic-guided placement of rAAV vectors into the live mouse brain using iontophoretic or nanoliter pressure injections. The methods discussed here will result in expression of fluorescent proteins in cell bodies, dendrites, and axons in targeted neurons, and can be easily adapted to address various experimental questions.