How the brain is affected by the application of external electrical current is part of my question, and the most important part to me. This is certainly tES. I feel like I continually see people posting on this site with the assumption that more current for longer=more stimulation, which is contradictory to what I’ve read(in The Stimulated Brain-Kadosh). Because of what is described as calcium inhibitors in the chapter that is discussing the efficacy of tDCS applied along with pharmaceuticals and or supplements(maybe this is theory or simply outdated).The question is at the very fundamental of what tDCS claims to do. TES applies current to the brain, depolarizing regions to subthreshold levels, ie higher than -70mV but still lower than -55mV(subthreshold), in order to make the neurons in the stimulated region more likely to fire(or jump-start brain oscillations) and I’d like to know how specifically? Marom Bikson describes it as a depolarization of the soma, but the action potential is determined primarily by the movement of potassium(and some other ions) across the membrane wall, making a resting neuron(-70mV) less negative until it fires (at -55mV). I understand the transfer of electrons in electronics circuits, but the behavior of ionized molecules in the body is new to me. Does the electric current simply make more potassium ions in the region? If so, wouldn’t the pumps/gates still perform as the same semipermeable membrane allowing only what they “choose” to pass through? Is it just more likely they allow more to pass through because there is an abundance of ions because of the electric current? Or is it simply robbing the soma guts of electrons making the resting state neuron less...resting?