These three problems may be resolved by a vector interpretation of Ohm’s Law: Eq. 2J=σE where J is the current density (e.g., referred to as current flow density by Nicholson and Freeman, 1975), E is the electric field, and σ is the conductivity tensor for the medium. This equation concisely describes the directional properties of the current flow through the medium, independent of any recording reference. Unfortunately, it is not expressed as a measurable voltage potential, which makes it unsuitable for probing the fields shown in Fig. 1, much less those from an EEG.
