In the Scholarpedia article on local field potentials (2013), I read:
The current view is that EEG and LFPs are generated by synchronized synaptic currents arising on cortical neurons, possibly through the formation of dipoles (Niedermeyer and Lopes da Silva, 1998; Nunez and Srinivasan, 2005).
There are three things I do not understand:
- What does "on neurons" mean? Why not "in" or "around neurons"?
- I assume that what is measured is the electric potential in an electric field that is generated by charges (the ions). So only the changes of the measured potential are due to currents, the potential itself (at any given point in time) is only due to the distribution of charges. Is that view correct? Independent of the nature of the charges.
- What exactly are the above mentioned dipoles? Of which are they formed and what is their size? (At least, the article says "possibly generated through the formation of dipoles".)
Does all this sum up to the picture that it is all and only about the ions that pass through the ligand-gated channels at a synapse and the electric field and potential generated by them, the contribution of all other charges being cancelled and filtered out?