The electric field system of an excitable cell

The specific microscopic origins of electromagnetic (EM) fields in excitable cell tissue have been underdetermined for a long time. A better understanding of the microscopic EM field origins directly facilitates an understanding of the origins of EEG and MEG signals, along with the role of EM coupling in cell excitability, developmental cues, regulatory processes underlying learning, and the general brain dynamics involved in all of these and of cognition generally. With the aim of isolating and describing the most plausible originating mechanism, the fundamental laws of electromagnetism, as applied to excitable cell tissue, were subjected to an extended review. A bridging form of the macroscopic EM volume conduction equations was constructed that was specially adapted to reveal the microscopic origins of the endogenous EM fields. The basis of the specialization was a focus on coherence between regions of transmembrane current activity expressed by a neuron during the passage of an action potential throughout its structure. A computational exploration of the equations, applied to a large, biologically realistic pyramidal cell, demonstrated that the coherent transmembrane current activity of spiking neurons can express a faint, unified, spatially extended, “line-of-sight-active” extra-neural EM field with complex structure and dynamics, all based on the operation of individual dipoles created by single ion channels, small ion channel aggregates, and large aggregates of the kind found in the synaptic cleft and elsewhere. The result is highly suggestive of an additional “line-of-sight” regulatory mechanism implemented as feedback delivered by EM coupling. This is consistent with recent empirical observations suggesting that this mechanism exists and operates in cortical tissue.