title: NMDAR-regulated dynamics of layer 4 neuronal dendrites during thalamocortical reorganization in neonates.
abstract: Thalamocortical (TC) connectivity is reorganized by thalamic inputs during postnatal development; however, the dynamic characteristics of TC reorganization and the underlying mechanisms remain unexplored. We addressed this question using dendritic refinement of layer 4 (L4) stellate neurons in mouse barrel cortex (barrel cells) as a model; dendritic refinement of L4 neurons is a critical component of TC reorganization through which postsynaptic L4 neurons acquire their dendritic orientation toward presynaptic TC axon termini. Simultaneous labeling of TC axons and individual barrel cell dendrites allowed in vivo time-lapse imaging of dendritic refinement in the neonatal cortex. The barrel cells reinforced the dendritic orientation toward TC axons by dynamically moving their branches. In N-methyl-D-aspartate receptor (NMDAR)-deficient barrel cells, this dendritic motility was enhanced, and the orientation bias was not reinforced. Our data suggest that L4 neurons have "fluctuating" dendrites during TC reorganization and that NMDARs cell autonomously regulate these dynamics to establish fine-tuned circuits.
authors.affiliation: Division of Neurogenetics, National Institute of Genetics, Mishima 411-8540, Japan; Department of Genetics, SOKENDAI, Mishima 411-8540, Japan.
authors.forename: Hidenobu
authors.initials: H
authors.lastname: Mizuno
authors.affiliation: Division of Neurogenetics, National Institute of Genetics, Mishima 411-8540, Japan; Department of Genetics, SOKENDAI, Mishima 411-8540, Japan.
authors.forename: Wenshu
authors.initials: W
authors.lastname: Luo
authors.affiliation: Division of Developmental Neurophysiology, National Institute for Physiological Sciences, Okazaki 444-8585, Japan.
authors.forename: Etsuko
authors.initials: E
authors.lastname: Tarusawa
authors.affiliation: Laboratory for Behavioral Genetics, RIKEN Brain Science Institute, Wako 351-0198, Japan.
authors.forename: Yoshikazu M
authors.initials: YM
authors.lastname: Saito
authors.affiliation: Division of Neurogenetics, National Institute of Genetics, Mishima 411-8540, Japan.
authors.forename: Takuya
authors.initials: T
authors.lastname: Sato
authors.affiliation: Division of Developmental Neurophysiology, National Institute for Physiological Sciences, Okazaki 444-8585, Japan; Department of Physiological Sciences, SOKENDAI, Okazaki 444-8585, Japan.
authors.forename: Yumiko
authors.initials: Y
authors.lastname: Yoshimura
authors.affiliation: Laboratory for Behavioral Genetics, RIKEN Brain Science Institute, Wako 351-0198, Japan.
authors.forename: Shigeyoshi
authors.initials: S
authors.lastname: Itohara
authors.affiliation: Division of Neurogenetics, National Institute of Genetics, Mishima 411-8540, Japan; Department of Genetics, SOKENDAI, Mishima 411-8540, Japan. Electronic address: tiwasato@nig.ac.jp.
authors.forename: Takuji
authors.initials: T
authors.lastname: Iwasato
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D002540:Cerebral Cortex / Q000166:cytology* / Q000502:physiology; D003712:Dendrites / Q000187:drug effects / Q000502:physiology*; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000235:genetics; D005260:Female; D018507:Gene Expression Regulation, Developmental / Q000502:physiology; D066298:In Vitro Techniques; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D008954:Models, Biological; D016202:N-Methylaspartate / Q000494:pharmacology; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D009434:Neural Pathways / Q000254:growth & development / Q000378:metabolism; D009474:Neurons / Q000166:cytology* / Q000187:drug effects; D016194:Receptors, N-Methyl-D-Aspartate / Q000235:genetics / Q000378:metabolism*; D013788:Thalamus / Q000502:physiology*; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid / Q000494:pharmacology
chemical_list: D018690:Excitatory Amino Acid Agonists; C121673:Gprin1 protein, mouse; D009419:Nerve Tissue Proteins; D016194:Receptors, N-Methyl-D-Aspartate; D016202:N-Methylaspartate; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid