PT - JOURNAL ARTICLE AU - Benjamin B. Scott AU - Timothy Gardner AU - Ni Ji AU - Michale S. Fee AU - Carlos Lois TI - Wandering Neuronal Migration in the Postnatal Vertebrate Forebrain AID - 10.1523/JNEUROSCI.2145-11.2012 DP - 2012 Jan 25 TA - The Journal of Neuroscience PG - 1436--1446 VI - 32 IP - 4 4099 - http://www.jneurosci.org/content/32/4/1436.short 4100 - http://www.jneurosci.org/content/32/4/1436.full SO - J. Neurosci.2012 Jan 25; 32 AB - Most non-mammalian vertebrate species add new neurons to existing brain circuits throughout life, a process thought to be essential for tissue maintenance, repair, and learning. How these new neurons migrate through the mature brain and which cues trigger their integration within a functioning circuit is not known. To address these questions, we used two-photon microscopy to image the addition of genetically labeled newly generated neurons into the brain of juvenile zebra finches. Time-lapse in vivo imaging revealed that the majority of migratory new neurons exhibited a multipolar morphology and moved in a nonlinear manner for hundreds of micrometers. Young neurons did not use radial glia or blood vessels as a migratory scaffold; instead, cells extended several motile processes in different directions and moved by somal translocation along an existing process. Neurons were observed migrating for ∼2 weeks after labeling injection. New neurons were observed to integrate in close proximity to the soma of mature neurons, a behavior that may explain the emergence of clusters of neuronal cell bodies in the adult songbird brain. These results provide direct, in vivo evidence for a wandering form of neuronal migration involved in the addition of new neurons in the postnatal brain.