Experience-Dependent, Rapid Structural Changes in Hippocampal Pyramidal Cell Spines

• Published in: Cerebral cortex (New York, N.Y. 1991) Vol. 19; no. 11; pp. 2572 - 2578
• Main Authors: Kitanishi, Takuma, Ikegaya, Yuji, Matsuki, Norio, Yamada, Maki K.
• Format: Journal Article
• Language: English
• Published: United States Oxford University Press 01.11.2009
• Subjects: Adaptation, Physiological - physiology; Animals; behavior; Dendrites - physiology; Dendrites - ultrastructure; Environment; hippocampus; immediate-early gene; Male; Mice; Neuronal Plasticity - physiology; plasticity; Pyramidal Cells - cytology; Pyramidal Cells - physiology; sparse coding; spine dynamics; immediate-early gene; plasticity; hippocampus; behavior; spine dynamics; sparse coding
• ISSN: 1047-3211; 1460-2199
• DOI: 10.1093/cercor/bhp012

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 florescent 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.