title: Wandering neuronal migration in the postnatal vertebrate forebrain.
abstract: 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.
authors.affiliation: Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: Benjamin B
authors.initials: BB
authors.lastname: Scott
authors.forename: Timothy
authors.initials: T
authors.lastname: Gardner
authors.forename: Ni
authors.initials: N
authors.lastname: Ji
authors.forename: Michale S
authors.initials: MS
authors.lastname: Fee
authors.forename: Carlos
authors.initials: C
authors.lastname: Lois
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D002465:Cell Movement / Q000502:physiology*; D046369:Finches / Q000254:growth & development*; D008297:Male; D009474:Neurons / Q000502:physiology*; D016548:Prosencephalon / Q000166:cytology* / Q000254:growth & development*