Do neurons generate monopolar current sources?
Alain Destexhe and Claude Bédard

Journal of Neurophysiology 108: 953-955, 2012.

Copy of the full paper (PDF)
According to the “standard model”, electric potentials such as the local field potential (LFP) or the electroencephalogram (EEG), are generated by current dipoles made by cerebral cortex neurons arranged in parallel. There is recent evidence that this standard model may be insufficient to account for LFP and EEG signals in the rat brain (Riera et al., J. Neurophysiol., 2012). In particular, the evidence points to the fact that monopolar components (not predicted by the standard model) are necessary to explain LFP and EEG signals. Here, we briefly summarize these findings, and then speculate on possible physical mechanisms to explain these surprising results.

See also follow-up commentary:

Bedard, C. and Destexhe, A. Electric monopoles are indeed compatible with Maxwell equations. J. Neurophysiol. 109: 1683, 2013 (PDF copy).