Synchronous activity of inhibitory networks in neocortex requires electrical synapses containing Connexin36

Inhibitory interneurons often generate synchronous activity as an emergent property of their interconnections. To determine the role of electrical syn apses in such activity, we constructed mice expressing histochemical report ers in place of the gap junction protein Cx36. Localization of the reporter with somatostatin and parvalbumin suggested that Cx36 was expressed largel y by Interneurons. Electrical synapses were common among cortical interneur ons in controls but were nearly absent in knockouts. A metabotropic glutama te receptor agonist excited LTS interneurons, generating rhythmic inhibitor y potentials in surrounding neurons of both wild-type and knockout animals. However, the synchrony of these rhythms was weaker and more spatially rest ricted in the knockout. We conclude that electrical synapses containing Cx3 6 are critical for the generation of widespread, synchronous inhibitory act ivity.