Abstract
EEGs are voltage drops of dendritic currents on the scalp and their electric sources are synaptic batteries. Decrease of extracellular impedance can increase dendritic currents, shift membrane potentials toward depolarization accordingly, and thus facilitate neural firing consequently. We attached a negative resistor on the scalp to realize the above-mentioned neural facilitation and call this technique transcranial Extracellular Impedance Control (tEIC) [1]. We performed behavioral experiments with tEIC and found significant modulation of brain functions in some cases. Current stimulation techniques such as tDCS and tACS are known to sometimes have modulation effects of brain functions. The most prominent difference between tEIC and tD/ACS is whether a resistor or a current source is attached on the scalp. If one would like to shift operating points in a running electric circuit, who would attach a new electric source to the circuit? tEIC does make sense, at least in the electric circuit sense, for modulation technique of brain functions. [1] A. Matani, et al., PLoS ONE, vol. 9, e0102834, 2014.
