Superdiffuse neuron migration in the postnatal brain
Songbirds generate new neurons that disperse widely throughout their brains throughout life. How these newborn neurons migrate through the adult brain tissue is unclear. We performed two-photon time lapse microscopy in GFP-expressing transgenic zebra finches to visualize migratory dynamics of cell populations in vivo. We tracked hundreds of migrating cells in the dorsal forebrain of awake animals for up to 12 hours. Migratory neurons dispersed in all directions and made frequent course changes, a pattern observed across male and females, juveniles and adults. Cells did not appear to follow blood vessels exclusively and histological analysis revealed that contact with radial glia was infrequent. Furthermore, cells appeared to move independently, and were largely uncorrelated in their speed, position and direction. Importantly, we found that migration dynamics across ages and brain regions were well fit by a superdiffusive model. These behaviors may reflect a specialized form of migration that enables neurons to flexibly navigate through the dense, functional circuitry of the postnatal brain.