title: Control of Spontaneous Ca2+ Transients Is Critical for Neuronal Maturation in the Developing Neocortex.
abstract: Neural activity plays roles in the later stages of development of cortical excitatory neurons, including dendritic and axonal arborization, remodeling, and synaptogenesis. However, its role in earlier stages, such as migration and dendritogenesis, is less clear. Here we investigated roles of neural activity in the maturation of cortical neurons, using calcium imaging and expression of prokaryotic voltage-gated sodium channel, NaChBac. Calcium imaging experiments showed that postmigratory neurons in layer II/III exhibited more frequent spontaneous calcium transients than migrating neurons. To test whether such an increase of neural activity may promote neuronal maturation, we elevated the activity of migrating neurons by NaChBac expression. Elevation of neural activity impeded migration, and induced premature branching of the leading process before neurons arrived at layer II/III. Many NaChBac-expressing neurons in deep cortical layers were not attached to radial glial fibers, suggesting that these neurons had stopped migration. Morphological and immunohistochemical analyses suggested that branched leading processes of NaChBac-expressing neurons differentiated into dendrites. Our results suggest that developmental control of spontaneous calcium transients is critical for maturation of cortical excitatory neurons in vivo: keeping cellular excitability low is important for migration, and increasing spontaneous neural activity may stop migration and promote dendrite formation.
authors.affiliation: Department of Biophysics, Kyoto University Graduate School of Science, Kyoto 606-8502, Japan.|CREST, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Bando
authors.affiliation: Department of Biophysics, Kyoto University Graduate School of Science, Kyoto 606-8502, Japan.|Cellular and Structural Physiology Institute, Nagoya University, Nagoya, Aichi 464-8601, Japan.
authors.forename: Katsumasa
authors.initials: K
authors.lastname: Irie
authors.affiliation: Department of Biophysics, Kyoto University Graduate School of Science, Kyoto 606-8502, Japan.|Cellular and Structural Physiology Institute, Nagoya University, Nagoya, Aichi 464-8601, Japan.
authors.forename: Takushi
authors.initials: T
authors.lastname: Shimomura
authors.affiliation: Institute for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Kyoto 606-8501, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Umeshima
authors.affiliation: Department of Biophysics, Kyoto University Graduate School of Science, Kyoto 606-8502, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Kushida
authors.affiliation: Institute for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University, Kyoto 606-8501, Japan.
authors.forename: Mineko
authors.initials: M
authors.lastname: Kengaku
authors.affiliation: Department of Biophysics, Kyoto University Graduate School of Science, Kyoto 606-8502, Japan.|Cellular and Structural Physiology Institute, Nagoya University, Nagoya, Aichi 464-8601, Japan.
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Fujiyoshi
authors.affiliation: Department of Biophysics, Kyoto University Graduate School of Science, Kyoto 606-8502, Japan.
authors.forename: Tomoo
authors.initials: T
authors.lastname: Hirano
authors.affiliation: Department of Biophysics, Kyoto University Graduate School of Science, Kyoto 606-8502, Japan.|CREST, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012, Japan.
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Tagawa
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002454:Cell Differentiation / Q000502:physiology*; D002465:Cell Movement / Q000502:physiology*; D003712:Dendrites / Q000378:metabolism; D051379:Mice; D019579:Neocortex / Q000254:growth & development* / Q000378:metabolism; D055495:Neurogenesis / Q000502:physiology; D009457:Neuroglia / Q000166:cytology*; D009474:Neurons / Q000166:cytology* / Q000502:physiology
chemical_list: D002118:Calcium
keywords: NaChBac; activity-dependent; calcium; cerebral cortex; development