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Cell Rep. 2015 Jan 13;10(2):162-9. doi: 10.1016/j.celrep.2014.12.016. Epub 2014 Dec 31.

Heterosynaptic structural plasticity on local dendritic segments of hippocampal CA1 neurons.

Author information

1
Center for Neuroscience, University of California Davis, Davis, CA 95616, USA.
2
Center for Neuroscience, University of California Davis, Davis, CA 95616, USA. Electronic address: kzito@ucdavis.edu.

Abstract

Competition between synapses contributes to activity-dependent refinement of the nervous system during development. Does local competition between neighboring synapses drive circuit remodeling during experience-dependent plasticity in the cerebral cortex? Here, we examined the role of activity-mediated competitive interactions in regulating dendritic spine structure and function on hippocampal CA1 neurons. We found that high-frequency glutamatergic stimulation at individual spines, which leads to input-specific synaptic potentiation, induces shrinkage and weakening of nearby unstimulated synapses. This heterosynaptic plasticity requires potentiation of multiple neighboring spines, suggesting that a local threshold of neural activity exists beyond which inactive synapses are punished. Notably, inhibition of calcineurin, IP3Rs, or group I metabotropic glutamate receptors (mGluRs) blocked heterosynaptic shrinkage without blocking structural potentiation, and inhibition of Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) blocked structural potentiation without blocking heterosynaptic shrinkage. Our results support a model in which activity-induced shrinkage signal, and not competition for limited structural resources, drives heterosynaptic structural and functional depression during neural circuit refinement.

PMID:
25558061
PMCID:
PMC4294981
DOI:
10.1016/j.celrep.2014.12.016
[Indexed for MEDLINE]
Free PMC Article

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