SELF-ORGANIZED BIOLOGICAL DYNAMICS AND NONLINEAR CONTROL
Edited by Jan Walleczek, Cambridge University Press, 2000, pp: xi+428, ISBN 0-521-62436-3(hb) ; QP517.C45S45 2000; Price: $110.00

---

Two workshops, "Self-organized Biodynamics and Control by Chemical and Electromagnetic Stimuli" (August 1996) and "Towards Information-based Interventions in Biological Systems: From Molecules to Dynamical Diseases" (August, 1998) were the genesis of this book. Jan Walleczek solicited contributions for the book from over 30 contributors who were primarily participants at the workshops. The book is not a compendium of conference proceedings, but rather a major effort to mark the emergence of a new scientific discipline "biodynamics".

Biodynamics can be defined as the study of the complex web of nonlinear dynamical interactions between and among molecules, cells and tissues, which give rise to the emergent functions of the biological system. In the past, much of the behavior of such systems defied intuition and the modeling of emergent biological system behavior was unsuccessful. In this book, the authors show how, by applying the appropriate mathematical tools and concepts of nonlinear dynamics, and its subdisciplines chaos and complexity studies, bioscientists have made some spectacular successes in modeling and prediction of biodynamical behavior in living organisms.

The book is divided in four sections. In the first section, various authors deal with biological response to stimuli. Biological systems often have unexpected and complex responses to various chemical and electrical stimuli. In response to stimuli the oscillatory patterns of the systems often change dramatically, periods of oscillations may suddenly double, and the system may shift unexpectedly between different modes of operation and behavior. Nonlinear models of various chemical and biological oscillators have been successful in predicting and modeling many of these surprising effects. As the writers demonstrate, given the complexity of these systems, this is rightly understood as an amazing and significant achievement.

In the first section also, the authors consider various chaotic patterns such as human heartbeat, and gait dynamics. Using fractal statistics, they illustrate that the underlying patterns of heartbeat, gait and many other biological patterns have long-range correlations that are both remarkable stable (over decades) and yet at the same time remarkably sensitive to disease, aging, and biological stressers such as infection and injury. These observations have opened whole new diagnostic possibilities that may allow monitoring, detection and even treatment of many disease conditions.

In the second section, the question is posed, "How do biological systems respond to electromagnetic stimuli?" Observations of biological systems demonstrate a diverse pattern of different nonlinear responses to static and oscillating electric and magnetic fields. The mechanisms underlying the nonlinear responses and how the stimuli impact the biological oscillations and biochemical networks are mostly unknown. The recent controversy on the dangers of low level electrical fields is not directly dealt with but the book. However, the book does discuss our limited understanding of electromagnetic interactions at the cellular and subcellular level. From the discussion, it is clear that current understanding of electromagnetic response is still at an early stage although non-linear approaches are suggesting pathways of research into the process.

The third and fourth sections deal with alternative factors in nonlinear approaches. In the third section, the writers consider biological stochastical dynamics which roughly can be thought of as how biodynamics are modified by consideration of the interaction of chaotic and truly random internal and external stimuli. Phenomena such as stochastic resonance where noise actually improves perception are discussed. Signal processing in the presence of noise is also a topic of discussion. In the fourth section of the book, nonlinear control of biological systems are discussed. Here, Epilepsy is discussed from the perspective of possible control mechanisms. In section one, Epilepsy was discussed as an example of a dynamical disease, and this further amplification of discussion further highlights the role of biodynamics in disease processes and treatment.

Sprinkled through the book are hints by the authors that dynamic behavior itself can also be used as a probe of biological mechanisms. Biodynamics, they suggest indicates that the different oscillatory dynamical states with different periodicities play a fundamental role in living organisms. These oscillations can have periods from fractions of a second to days and may exist in periodic, aperiodic, quasi-periodic and chaotic regimes. Furthermore, it is now thought that oscillatory dynamics play an integral part in perception (visual, auditory, etc.) , thinking, ovarian cycle, and host of fundamental metabolic processes. Some examples of oscillations under study are intracellular concentrations of calcium, adenosine triphosphate, nicotinamide adenine dinucleotide phosphate and their role in cell biology.

Overall, this is an exciting book for anyone doing research at the frontier of the biological sciences. Those in the other scientific disciplines may find the reading somewhat difficult because of the extensive use of biological jargon but nevertheless those willing to expend some effort will be amply rewarded. Overall the book provides an excellent chance to quickly come to the forefront of a scientific field. The successful application of nonlinear concepts to biological phenomena also suggests that other applications in fields with known but puzzling oscillatory behavior may be fruitful.

Collin C. Carbno
Saskatchewan Telecommunications