“Cross-Modality” Experiments in Humans

Abstract

As emphasized in previous chapters, the complex dynamics of compound potentials and resonance phenomena of the brain might play one of the most important roles in brain organization. On the basis of earlier research on the dynamics of EEG and ERPs, the present chapter focuses on an experimental approach involving cross-modality stimulation. Such experiments help to clarify functional correlates of the alpha and theta response, i.e., response components found by applying Fourier analysis to EPs and ERPs. The terms “theta” and “alpha response” refer to relatively short periods of damped oscillations that are not due to filtering techniques or to Fourier artifacts. Most probably they are due to the effects of change of the EEG immediately following stimulation and visible even in single EEG-EP epochs (see Chap. 9). The “alpha response,” e.g., is defined as the oscillatory EEG or MEG activity in the first 200–300 ms following sensory stimulation.