The local electric field can be strong
Figure 5. The local strength of the electric field was measured by subtraction of the local field potential obtained from neighboring recording points (150 microns apart). The average positive and negative field strength was approxiamtely 2.2 mV/mm but ranged up to 4 mV/mm.
Slow oscillation is accompanied by a pronounced endogenous electric field (EF) in vivo (several mV/mm amplitude).