Exploring gap junction location and density in electrically coupled hippocampal oriens interneurons

Interneuronal networks, connected by chemical and electrical (gap junctions) synapses, are important for shaping population field rhythms in the hippocampus. Recently, weak electrical coupling has been found between oriens interneurons in the CA1 region of the hippocampus. Action potentials in one cell produced spikelets in the connected cell. We use a two-cell model network of oriens interneurons to determine the dendritic location and strength of gap junctions needed to match experimentally measured spikelet characteristics. The location of the gap junctions is predicted to be 150–200 μm from the soma, corresponding to electrotonic lengths of 0.17–0.23 as measured from the soma to the dendrite location and 0.71–1.04 as measured from the dendritic location to the soma, with a conductance of 500–800 pS.