Maturation of a recurrent excitatory neocortical circuit by experience-dependent unsilencing of newly-formed dendritic spines

MC Ashby, JT Isaac

Research output: Contribution to journalArticle (Academic Journal)

34 Citations (Scopus)
519 Downloads (Pure)


Local recurrent excitatory circuits are ubiquitous in neocortex, yet little is known about their development or architecture. Here we introduce a quantitative technique for efficient single-cell resolution circuit mapping using 2-photon (2P) glutamate uncaging and analyze experience-dependent neonatal development of the layer 4 barrel cortex local excitatory circuit. We show that sensory experience specifically drives a 3-fold increase in connectivity at postnatal day (P) 9, producing a highly recurrent network. A profound dendritic spinogenesis occurs concurrent with the connectivity increase, but this is not experience dependent. However, in experience-deprived cortex, a much greater proportion of spines lack postsynaptic AMPA receptors (AMPARs) and synaptic connectivity via NMDA receptors (NMDARs) is the same as in normally developing cortex. Thus we describe a approach for quantitative circuit mapping and show that sensory experience sculpts an intrinsically developing template network, which is based on NMDAR-only synapses, by driving AMPARs into newly formed silent spines.
Original languageEnglish
Pages (from-to)510 - 521
Number of pages12
Issue number3
Publication statusPublished - 12 May 2011


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