I'm surprised to see no mention of the two mechanisms that jump out at me as candidate explanations: a) standard electrical induction b) standard conductance vi

I'm surprised to see no mention of the two mechanisms that jump out at me as candidate explanations: a) standard electrical induction b) standard conductance via the extracellular matrix (https://en.wikipedia.org/wiki/Extracellular_matrix https://en.wikipedia.org/wiki/Extracellular_matrix) W/r/t b), they do claim that they sliced the hippocampus and then observed activity induced across the preserved gap, but it's not clear (from my light read) that the tissues weren't still touching such that the axons/dendrites were gapped, but the ECM was not; if this were the case, then I'd expect signals to propagate across severed neuronal connections via standard conductance in the ECM. More please!