title: Long-term stability of axonal boutons in the mouse barrel cortex.
abstract: Many lines of evidence indicate that postsynaptic dendritic spines are plastic during development and largely stable in adulthood. It remains unclear to what degree presynaptic axonal terminals undergo changes in the developing and mature cortex. In this study, we examined the formation and elimination of fluorescently-labeled axonal boutons in the living mouse barrel cortex with transcranial two-photon microscopy. We found that the turnover of axonal boutons was significantly higher in 3-week-old young mice than in adult mice (older than 3 months). There was a slight but significant net loss of axonal boutons in mice from 1 to 2 months of age. In both young and adult barrel cortex, axonal boutons existed for at least 1 week were less likely to be eliminated than those recently-formed boutons. In adulthood, 80% of axonal boutons persisted over 12 months and enriched sensory experience caused a slight but not significant increase in the turnover of axonal boutons over 2-4 weeks. Thus, similar to postsynaptic dendritic spines, presynaptic axonal boutons show remarkable stability after development ends. This long-term stability of synaptic connections is likely important for reliable sensory processing in the mature somatosensory cortex.
authors.affiliation: Drug Discovery Center, Key Laboratory of Chemical Genomics, Peking University Shenzhen Graduate School, Shenzhen, 518055, China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Qiao
authors.affiliation: Drug Discovery Center, Key Laboratory of Chemical Genomics, Peking University Shenzhen Graduate School, Shenzhen, 518055, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Ma
authors.affiliation: Drug Discovery Center, Key Laboratory of Chemical Genomics, Peking University Shenzhen Graduate School, Shenzhen, 518055, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Li
authors.affiliation: Department of Neuroscience and Physiology, Skirball Institute, New York University School of Medicine, New York, New York, 10016.
authors.forename: Jin-Wu
authors.initials: JW
authors.lastname: Tsai
authors.affiliation: Department of Anesthesiology, New York University School of Medicine, New York, New York, 10016.
authors.forename: Guang
authors.initials: G
authors.lastname: Yang
authors.affiliation: Drug Discovery Center, Key Laboratory of Chemical Genomics, Peking University Shenzhen Graduate School, Shenzhen, 518055, China.|Department of Neuroscience and Physiology, Skirball Institute, New York University School of Medicine, New York, New York, 10016.
authors.forename: Wen-Biao
authors.initials: WB
authors.lastname: Gan
mesh_terms: D000818:Animals; D051379:Mice; D008822:Mice, Transgenic; D055495:Neurogenesis / Q000502:physiology*; D009473:Neuronal Plasticity / Q000502:physiology; D017729:Presynaptic Terminals / Q000648:ultrastructure*; D013003:Somatosensory Cortex / Q000254:growth & development* / Q000648:ultrastructure*
keywords: axonal bouton; sensory enrichment; synaptic plasticity; two-photon imaging