This book is the fourth in a series based on conferences sponsored by the Metroplex Institute for Neural Dynamics (MIND), an interdisciplinary organization of Dallas-Fort Worth area neural network professionals in both academia and industry. This topic was chosen as the focus for this special issue because of the increasing interest by neuroscientists and psychologists in both rhythmic and chaotic activity patterns observed in the nervous system. Neither the mathematical structure of neural oscillations nor their functional significance is precisely understood. There are a great many open problems in both the structure and function of neural oscillations, whether rhythmic, chaotic, or a combination of the two, and many of these problems are dealt with in the chapters of this book.