Regulation of Radial Glial Motility by Visual Experience

Radial glia in the developing optic tectum express the key guidance molecules responsible for topographic targeting of retinal axons. However, the extent to which the radial glia are themselves influenced by retinal inputs and visual experience remains unknown. Using multiphoton live imaging of radial glia in the optic tectum of intact Xenopus laevis tadpoles in conjunction with manipulations of neural activity and sensory stimuli, radial glia were observed to exhibit spontaneous calcium transients that were modulated by visual stimulation. Structurally, radial glia extended and retracted many filopodial processes within the tectal neuropil over minutes. These processes interacted with retinotectal synapses and their motility was modulated by nitric oxide (NO) signaling downstream of neuronal NMDA receptor (NMDAR) activation and visual stimulation. These findings provide the first in vivo demonstration that radial glia actively respond both structurally and functionally to neural activity, via NMDAR-dependent NO release during the period of retinal axon ingrowth.Canadian Institutes of Health ResearchCanadian Institutes of Health Research (CIHR)EJLB FoundationEJLB FoundationNational Alliance for Research on Schizophrenia and DepressionNational Alliance for Research on Schizophrenia and DepressionMarch of DimesMarch of DimesNatural Sciences and Engineering Research Council of CanadaNatural Sciences and Engineering Research Council of CanadaFonds de la recherche en sante QuebecFonds de la recherche en sante QuebecFundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)[07/02938-5]Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)[05/00587-5]Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq)[301303/06-1]Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq