Selective Maturation of Temporal Dynamics of Intracortical Excitatory Transmission at the Critical Period Onset

Cell Rep. 2016 Aug 9;16(6):1677-1689. doi: 10.1016/j.celrep.2016.07.013. Epub 2016 Jul 28.

Abstract

Although the developmental maturation of cortical inhibitory synapses is known to be a critical factor in gating the onset of critical period (CP) for experience-dependent cortical plasticity, how synaptic transmission dynamics of other cortical synapses are regulated during the transition to CP remains unknown. Here, by systematically examining various intracortical synapses within layer 4 of the mouse visual cortex, we demonstrate that synaptic temporal dynamics of intracortical excitatory synapses on principal cells (PCs) and inhibitory parvalbumin- or somatostatin-expressing cells are selectively regulated before the CP onset, whereas those of intracortical inhibitory synapses and long-range thalamocortical excitatory synapses remain unchanged. This selective maturation of synaptic dynamics results from a ubiquitous reduction of presynaptic release and is dependent on visual experience. These findings provide an additional essential circuit mechanism for regulating CP timing in the developing visual cortex.

MeSH terms

  • Animals
  • Electric Stimulation / methods
  • Excitatory Postsynaptic Potentials / drug effects
  • Excitatory Postsynaptic Potentials / physiology
  • Mice
  • Neuronal Plasticity* / drug effects
  • Neuronal Plasticity* / physiology
  • Parvalbumins / pharmacology
  • Synapses / drug effects
  • Synapses / physiology*
  • Synaptic Transmission* / drug effects
  • Visual Cortex / drug effects
  • Visual Cortex / growth & development*

Substances

  • Parvalbumins