['Recently we have shown that transcranial random noise (tRNS) and 140\xa0Hz transcranial alternating current stimulations (tACS), applied over the primary motor cortex (M1) and using 10\xa0min stimulation duration and 1\xa0mA intensity, significantly increases cortical excitability as measured by motor evoked potentials at rest before and after stimulation.', 'Here, by decreasing the stimulation intensity in 0.2\xa0mA steps from 1.0\xa0mA, we investigate to what extent intensity depends on the induced after-effects.', 'All twenty-five subjects participated in two different experimental sessions each. They received tACS using 140\xa0Hz frequency and full spectrum tRNS at five different intensities on separate days. Sham stimulation was used as a control.', 'Instead of receiving a simple threshold, unexpectedly, in these two independent data sets at threshold intensities of 0.4\xa0mA we found a switch of the already known excitation achieved with an intensity of 1\xa0mA to inhibition. The intermediate intensity ranges of 0.6 and 0.8\xa0mA had no effect at all. Interestingly, the inhibition produced by 140\xa0Hz tACS was stronger than that induced by tRNS.'] Does close to threshold transcranial electrical stimulation preferentially activate inhibitory networks before switching to excitation with higher intensities?