Electrical synapses between GABA-releasing interneurons

Although gap junctions were first demonstrated in the mammalian brain about 30 years ago, the distribution and role of electrical synapses have remain ed elusive. A series of recent reports has demonstrated that inhibitory int erneurons in the cerebral cortex, thalamus, striatum and cerebellum are ext ensively interconnected by electrical synapses. Investigators have used pai red recordings to reveal directly the presence of electrical synapses among identified cell types. These studies indicate that electrical coupling is a fundamental feature of local inhibitory circuits and suggest that electri cal synapses define functionally diverse networks of GABA-releasing interne urons. Here, we discuss these results, their possible functional significan ce and the insights into neuronal circuit organization that have emerged fr om them.