title: Experience-dependent, rapid structural changes in hippocampal pyramidal cell spines.
abstract: Morphological changes in dendritic spines may contribute to the fine tuning of neural network connectivity. The relationship between spine morphology and experience-dependent neuronal activity, however, is largely unknown. In the present study, we combined 2 histological analyses to examine this relationship: 1) Measurement of spines of neurons whose morphology was visualized in brain sections of mice expressing membrane-targeted green fluorescent protein (Thy1-mGFP mice) and 2) Categorization of CA1 neurons by immunohistochemical monitoring of Arc expression as a putative marker of recent neuronal activity. After mice were exposed to a novel, enriched environment for 60 min, neurons that expressed Arc had fewer small spines and more large spines than Arc-negative cells. These differences were not observed when the exploration time was shortened to 15 min. This net-balanced structural change is consistent with both synapse-specific enhancement and suppression. These results provide the first evidence of rapid morphological changes in spines that were preferential to a subset of neurons in association with an animal's experiences.
authors.affiliation: Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo 113-0033, Japan.
authors.forename: Takuma
authors.initials: T
authors.lastname: Kitanishi
authors.forename: Yuji
authors.initials: Y
authors.lastname: Ikegaya
authors.forename: Norio
authors.initials: N
authors.lastname: Matsuki
authors.forename: Maki K
authors.initials: MK
authors.lastname: Yamada
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology*; D000818:Animals; D003712:Dendrites / Q000502:physiology* / Q000648:ultrastructure*; D004777:Environment; D008297:Male; D051379:Mice; D009473:Neuronal Plasticity / Q000502:physiology*; D017966:Pyramidal Cells / Q000166:cytology* / Q000502:physiology*