Toward a Theory of Brain Oscillations

Abstract

The main principles derived from the results presented in this book may be summarized as follows:

• 1. Natural frequencies of the brain (EEG frequencies) and resonance principle: The brain has several types of natural oscillatory activities in various frequency ranges: “delta,” “theta,” “alpha,” “gamma,” and “highest frequencies.” These oscillations may occur spontaneously (visible in the EEG), or can be emitted, induced, or evoked (visible in the EP or ERP). The phase-locking and amplitude increase of these oscillations occurring upon application of a stimulus are regarded as signs of a resonance phenomenon.

• 2. The brain’s natural oscillations (EEG frequencies) are also recorded at the cellular level. Cellular spontaneous and evoked and induced ryhytms are also observed in 10 Hz, 40 Hz, and beta and delta frequencies (see Chap. 9)

• 3. The EEG is not noise: chaotic signals. The natural oscillations are not always noise but probably reflect properties of chaotic attractors: We use the expression quasi-deterministic to describe this oscillatory behavior (see Chap. 10).