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

Neuron. 2011 May 12;70(3):510-21. doi: 10.1016/j.neuron.2011.02.057.


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.

Publication types

  • Research Support, N.I.H., Intramural

MeSH terms

  • Action Potentials / drug effects
  • Action Potentials / physiology
  • Age Factors
  • Animals
  • Animals, Newborn
  • Brain Mapping
  • Dendritic Spines / drug effects
  • Dendritic Spines / physiology*
  • Electric Stimulation / methods
  • Excitatory Postsynaptic Potentials / drug effects
  • Excitatory Postsynaptic Potentials / physiology
  • Glutamic Acid / pharmacology
  • In Vitro Techniques
  • Mice
  • Nerve Net / growth & development*
  • Neurons / cytology*
  • Neurons / drug effects
  • Patch-Clamp Techniques / methods
  • Photic Stimulation / methods
  • Probability
  • Sensory Deprivation / physiology*
  • Somatosensory Cortex / cytology*
  • Somatosensory Cortex / growth & development


  • Glutamic Acid