Electrical synapses are found in vertebrate and invertebrate nervous systems. The cellular basis of these synapses is the gap junction, a group of intercellular channels that mediate direct communication between adjacent neurons. Similar to chemical synapses, electrical connections are modifiable and their variations in strength provide a mechanism for reconfiguring neural circuits. In addition, electrical synapses dynamically regulate neural circuits through properties without equivalence in chemical transmission. Because of their continuous nature and bidirectionality, electrical synapses allow electrical currents underlying changes in membrane potential to leak to ‘coupled’ partners, dampening neuronal excitability and altering their integrative properties. Remarkably, this effect can be transiently alleviated when comparable changes in membrane potential simultaneously occur in each of the coupled neurons, a phenomenon that is dynamically dictated by the timing of arriving signals such as synaptic potentials. By way of this mechanism, electrical synapses influence synaptic integration and action potential generation, imparting an additional layer of dynamic complexity to neural circuits.
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The authors thank D. S. Faber and A. Marty for valuable comments on the manuscript. The authors are indebted to the 2013 Grass Laboratory for the stimulating environment. The authors are supported by the Grass Foundation, the Munich Center for NeuroSciences (P.A.) and US National Institutes of Health grants DC03186, DC011099, NS055726, NS085772 and NS0552827 (A.E.P.).
Nature Reviews Neuroscience thanks G. Awatramani, E. Marder and M. Veruki for their contribution to the peer review of this work.
The authors declare no competing interests.
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
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About this article
Response to coincident inputs in electrically coupled primary afferents is heterogeneous and is enhanced by H-current (IH) modulation
Journal of Neurophysiology (2019)