Transcranial alternating-current stimulation in the frequency range of 1–100 Hz has come to be used routinely in electroencephalogram studies of brain function through entrainment of neuronal oscillations. It turned out, however, to be highly non-trivial to remove the strong stimulation signal, including its harmonic and non-harmonic distortions, as well as various induced higher-order artifacts from the EEG data recorded during the stimulation. In this paper, we discuss some of the problems encountered and present methodological approaches aimed at overcoming them. To (...) illustrate the mechanisms of artifact induction and the proposed removal strategies, we use data obtained with the help of a schematic demonstrator setup as well as human-subject data. (shrink)

The idea of the genetic unity of all mankind is an integral part of Christian teaching. The purpose of this brief survey is to illustrate its role within the Greek patristic tradition, and then to point to a few examples from modern science which lend support to this ancient idea.