Chaos in Human Brain Phase Transition


Book Description

From a theoretical equation, modeling the dynamic of the time-dependent coefficients of the first and the second Karhunen-Loeve (KL) expansion of a superconducting quantum interference device (SQUID) signal, chaotic phase transition has been studied in the human brain. Through numerical investigations, the bifurcation diagram and the dynamic of Lyapunov exponent have been plotted. These diagrams reveal that throughout the variation of the control parameter here the frequency of the acoustic stimulus, the brain bifurcates from chaotic states to periodic or to quasiperiodic one. Also a chaotic phase portrait of the KL modes and its corresponding Poincaré section have been plotted. The origin of chaos in the human brain could be due to the self-organizing processes of nonequilibrium phase transition occurring in the electrochemical physiological phenomena of the complex nerve cells and neural assembly. Besides, the occurrence of chaos in the absence of stimuli has been remarked and thought to be due to the fact that an intrinsic brain could be chaotic. Moreover it has been found that the range of frequency for which the brain is forced to behave periodically could be harmful to the thinking process.




Criticality in Neural Systems


Book Description

Neurowissenschaftler suchen nach Antworten auf die Fragen, wie wir lernen und Information speichern, welche Prozesse im Gehirn verantwortlich sind und in welchem Zeitrahmen diese ablaufen. Die Konzepte, die aus der Physik kommen und weiterentwickelt werden, können in Medizin und Soziologie, aber auch in Robotik und Bildanalyse Anwendung finden. Zentrales Thema dieses Buches sind die sogenannten kritischen Phänomene im Gehirn. Diese werden mithilfe mathematischer und physikalischer Modelle beschrieben, mit denen man auch Erdbeben, Waldbrände oder die Ausbreitung von Epidemien modellieren kann. Neuere Erkenntnisse haben ergeben, dass diese selbstgeordneten Instabilitäten auch im Nervensystem auftreten. Dieses Referenzwerk stellt theoretische und experimentelle Befunde internationaler Gehirnforschung vor zeichnet die Perspektiven dieses neuen Forschungsfeldes auf.




Chaos in Brain Function


Book Description

The analysis of deterministic chaos is currently an active field in many branches of research. Mathematically all nonlinear dynamical systems with more than two degrees of freedom can generate chaos, becoming unpredictable over a longer time scale. The brain is a nonlinear system par excellence. Accordingly, the concepts of chaotic dynamics have found, in the last five years, an important application in research on compound electrical activity of the brain. The present volume seeks to cover most of the relevant studies in the newly emerging field of chaotic attractors in the brain. This volume is essentially a selection and reorganization of contri butions from the first two volumes in the Springer Series in Brain Dynamics, which were based on conferences held in 1985 and 1987 in Berlin. It also includes (a) a survey of progress in the recording of evoked oscillations of the brain both at the cellular and EEG levels and (b) an agenda for research on chaotic dynamics. Although the first publications pointing out evidence of chaotic behavior of the EEG did not appear until the beginning of 1985, the presence of the pioneering scientists in this field gave the participants at the first conference (volume 1) a strong impulse toward this field. For me, as conference organizer, having been for a long time active in nonlinear EEG research, the integration of this topic was self-evident; however, the enthusiasm of the conference participants was greater than expected.




Measuring Chaos In The Human Brain - Proceedings Of The Conference


Book Description

This conference brought together scientists from diverse disciplines such as biomedical and electrical engineering, mathematics, physics, neurology, neuroscience, psychophysiology and psychology to discuss the application of nonlinear dynamics in the study of brain function. This is a relatively new field which involves measuring the properties of chaotic strange attractors in the human EEG. Probably the earliest and still most exciting result in the field is that 'the more chaos the better' is the rule in many physiological areas. We have only the most speculative ideas about why the brain might be chaotic and what the implications are if it really is. The potential is unimaginably large. This volume will serve to inspire others to pursue research in this field and point the way in some promising directions.




Modeling Phase Transitions in the Brain


Book Description

Foreword by Walter J. Freeman. The induction of unconsciousness using anesthetic agents demonstrates that the cerebral cortex can operate in two very different behavioral modes: alert and responsive vs. unaware and quiescent. But the states of wakefulness and sleep are not single-neuron properties---they emerge as bulk properties of cooperating populations of neurons, with the switchover between states being similar to the physical change of phase observed when water freezes or ice melts. Some brain-state transitions, such as sleep cycling, anesthetic induction, epileptic seizure, are obvious and detected readily with a few EEG electrodes; others, such as the emergence of gamma rhythms during cognition, or the ultra-slow BOLD rhythms of relaxed free-association, are much more subtle. The unifying theme of this book is the notion that all of these bulk changes in brain behavior can be treated as phase transitions between distinct brain states. Modeling Phase Transitions in the Brain contains chapter contributions from leading researchers who apply state-space methods, network models, and biophysically-motivated continuum approaches to investigate a range of neuroscientifically relevant problems that include analysis of nonstationary EEG time-series; network topologies that limit epileptic spreading; saddle--node bifurcations for anesthesia, sleep-cycling, and the wake--sleep switch; prediction of dynamical and noise-induced spatiotemporal instabilities underlying BOLD, alpha-, and gamma-band Hopf oscillations, gap-junction-moderated Turing structures, and Hopf-Turing interactions leading to cortical waves.




Research Advances in Chaos Theory


Book Description

The subject of chaos has invaded practically every area of the natural sciences. Weather patterns are referred to as chaotic. There are chemical reactions and chaotic evolution of insect populations. Atomic and molecular physics have also seen the emergence of the study of chaos in these microscopic domains. This book examines the issue of chaos in nonlinear and dynamical systems, quantum mechanics, biology, and economics.




Phase Transitions


Book Description

Phase transitions--changes between different states of organization in a complex system--have long helped to explain physics concepts, such as why water freezes into a solid or boils to become a gas. How might phase transitions shed light on important problems in biological and ecological complex systems? Exploring the origins and implications of sudden changes in nature and society, Phase Transitions examines different dynamical behaviors in a broad range of complex systems. Using a compelling set of examples, from gene networks and ant colonies to human language and the degradation of diverse ecosystems, the book illustrates the power of simple models to reveal how phase transitions occur. Introductory chapters provide the critical concepts and the simplest mathematical techniques required to study phase transitions. In a series of example-driven chapters, Ricard Solé shows how such concepts and techniques can be applied to the analysis and prediction of complex system behavior, including the origins of life, viral replication, epidemics, language evolution, and the emergence and breakdown of societies. Written at an undergraduate mathematical level, this book provides the essential theoretical tools and foundations required to develop basic models to explain collective phase transitions for a wide variety of ecosystems.




Brain-behavior Continuum, The: The Subtle Transition Between Sanity And Insanity


Book Description

This book is a comprehensive overview of the main current concepts in brain cognitive activities at the global, collective (or network) level, with a focus on transitions between normal neurophysiology and brain pathological states. It provides a unique approach of linking molecular and cellular aspects of normal and pathological brain functioning with their corresponding network, collective and dynamical manifestations that are subsequently extended to behavioral manifestations of healthy and diseased brains. This book introduces a high-level perspective, searching for simplification amongst the structural and functional complexity of nervous systems by consideration of the distributed interactions that underlie the collective behavior of the system. The authors hope that this approach could promote a global comprehensive understanding of high-level laws behind the elementary biological processes in the neuroscientific community, while, perhaps, introducing elements of biological complexities to the mathematical/computational readership. The title of the book refers to the main point of the monograph: that there is a smooth continuum between distinct brain activities resulting in different behaviors, and that, due to the plastic nature of the brain, the behavior can also alter the brain function, thus rendering artificial the boundaries between the brain and its behavior.




Analysis of Neurophysiological Brain Functioning


Book Description

The analysis of neurophysiological brain function is a highly interdisciplinary field of research. In addition to the traditional areas of psychology and neurobiology, various other scientific disciplines, such as physics, mathematics, computer science, and engineering, are involved. The book reviews a wide spectrum of model-based analyses of neurophysiological brain function. In the first part, physical and physiological models and synergetic concepts are presented. The second part focuses on analysis methods and their applications to EEG/MEG data sets. It reviews methods of source localization, the investigation of synchronization processes, and spatio-temporal modeling based on dynamical systems theory. The book includes contributions by well-known scientists such as Hermann Haken, Scott Kelso and Paul Nunez, among others. It is written for students and scientists from all the above-mentioned fields.




Coordination Dynamics: Issues and Trends


Book Description

This book brings together scientists from all over the world who have defined and developed the field of Coordination Dynamics. Grounded in the concepts of self-organization and the tools of nonlinear dynamics, appropriately extended to handle informational aspects of living things, Coordination Dynamics aims to understand the coordinated functioning of a variety of different systems at multiple levels of description. The book addresses the themes of Coordination Dynamics and Dynamic Patterns in the context of the following topics: Coordination of Brain and Behavior, Perception-Action Coupling, Control, Posture, Learning, Intention, Attention, and Cognition.