Ephaptic coupling to endogenous electric field activity: why bother?

•Dynamic, endogenous electric field activity is the hallmark of the living brain.•Extracellular electric fields impact the membrane potential via a feedback (ephaptic) mechanism.•Characterizing ephaptic coupling at the level of synapses, single neurons and networks.•Translational neuroscience implications of understanding and characterizing ephaptic coupling.

There has been a revived interest in the impact of electric fields on neurons and networks. Here, we discuss recent advances in our understanding of how endogenous and externally imposed electric fields impact brain function at different spatial (from synapses to single neurons and neural networks) and temporal scales (from milliseconds to seconds). How such ephaptic effects are mediated and manifested in the brain remains a mystery. We argue that it is both possible (based on available technologies) and worthwhile to vigorously pursue such research as it has significant implications on our understanding of brain processing and for translational neuroscience.