Proximally targeted GABAergic synapses and gap junctions synchronize cortical interneurons

Nat Neurosci. 2000 Apr;3(4):366-71. doi: 10.1038/73936.


Networks of GABAergic interneurons are implicated in synchronizing cortical activity at gamma frequencies (30-70 Hz). Here we demonstrate that the combined electrical and GABAergic synaptic coupling of basket cells instantaneously entrained gamma-frequency postsynaptic firing in layers 2/3 of rat somatosensory cortex. This entrainment was mediated by rapid curtailment of gap junctional coupling potentials by GABAA receptor-mediated IPSPs. Electron microscopy revealed spatial proximity of gap junctions and GABAergic synapses on somata and dendrites. Electrical coupling alone entrained postsynaptic firing with a phase lag, whereas unitary GABAergic connections were ineffective in gamma-frequency phasing. These observations demonstrate precise spatiotemporal mechanisms underlying action potential timing in oscillating interneuronal networks.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Action Potentials / drug effects
  • Action Potentials / physiology
  • Age Factors
  • Animals
  • Bicuculline / pharmacology
  • Cell Communication / physiology*
  • Excitatory Postsynaptic Potentials / physiology
  • GABA Antagonists / pharmacology
  • Gap Junctions / physiology*
  • Gap Junctions / ultrastructure
  • Interneurons / cytology
  • Interneurons / physiology*
  • Microscopy, Electron
  • Rats
  • Rats, Wistar
  • Synapses / physiology*
  • Synapses / ultrastructure
  • gamma-Aminobutyric Acid / physiology*


  • GABA Antagonists
  • gamma-Aminobutyric Acid
  • Bicuculline