Model 1a, Electrical Synapses
To test the necessity of the EOCD electrical synapse in the model, the amplitude of the Iclamp current injection was systematically decreased and the relationship between spike number and delay was examined. The maximum conductance of the chemical EPSP component was increased in unison with this manipulation to produce spike number responses of more than zero for the smallest delays, in order to reasonably maintain the net depolarizing input to the model cell. Decreasing the amplitude of the electrical component to 75% of the model value was sufficient to totally abolish the graded spike number response of the cell (not shown). This suggests that, at least under the input paradigm described by this particular model, the EOCD electrical synapse input component is necessary for maintenance of the desired neural code (even though this electrical synapse is not known to exist in vivo).