Dynamical theory and novel 4-D colorimetric method reveal modus operandi of intact living brain

January 22, 2009

For the brain to achieve its intricate functions such as perception, action, attention and decision making, neural regions have to work together yet still retain their specialized roles. Excess or lack of timely coordination between brain areas lies at the core of a number of psychiatric and neurological disorders such as epilepsy, schizophrenia, autism, Parkinson's disease, sleep disorders and depression. How the brain is coordinated is a complex and difficult problem in need of new theoretical insights as well as new methods of investigation.

In groundbreaking research published in the January 2009 issue and featured on the cover of Progress in Neurobiology, researchers at Florida Atlantic University's Center for Complex Systems and Brain Sciences in the Charles E. Schmidt College of Science propose a theoretical model of the brain's coordination dynamics and apply a novel 4D colorimetric method to human neurophysiological data collected in the laboratory. The article, titled "Brain coordination dynamics: true and false faces of phase synchrony and metastability," is co-authored by Drs. Emmanuelle Tognoli, an expert in neurophysiology and research assistant professor in the Center's Human Brain and Behavior Laboratory, and J. A. Scott Kelso, the Glenwood and Martha Creech Eminent Scholar in Science and founder of the Center. The authors' theory and data show that both tendencies co-occur in the brain and are essential for its normal function. Their research demonstrates that coordination involves a subtle kind of ballet in the brain, and like dancers, cortical areas are capable of coming together as an ensemble (integration) while still exhibiting a tendency to do their own thing (segregation).

"A lot of emphasis in neuroscience these days is on what the parts do," said Kelso. "But understanding the coordination of multiple parts in a complex system such as the brain is a fundamental challenge. Using our approach, key predictions of cortical coordination dynamics can now be tested, thereby revealing the essential modus operandi of the intact living brain."

Tognoli and Kelso developed a novel colorimetric technique that simultaneously maps four dimensions of brain data (magnitude, 2D of cortical surface and time) in order to capture true synchronization in electroencephalographic (EEG) signals. Because of the fourth dimension afforded by this colorimetric method, it is possible to observe and interpret oscillatory activity of the entire brain as it evolves in time, millisecond by millisecond. Moreover, the authors' method applies to continuous non-averaged EEG data thereby de-emphasizing the notion of "an average brain." The authors demonstrate that only in continuous EEG can real synchronization be sorted from false synchronization - a kind of synchronization that arises from the spread of electrical fields and volume conduction rather than from genuine interactions between brain areas.

Most of the time, activity from multiple brain areas look coordinated; however, in actuality, there is far less synchrony than what appears to be. With the support of mathematical models that reproduce the biases of real brain records in synthetic data, the authors show how to tell apart real and false episodes of synchronization. For the first time, true episodes of brain coordination can be spotted directly in EEG records and carefully analyzed.

In addition to shedding insight on the way the brain normally operates, Tognoli and Kelso's research provides a much-needed framework to understand the coordination dynamics of brain areas in a variety of pathological conditions. Their approach allows a precise parsing of "brain states" and is likely to open up new ways to study therapeutic interventions, in particular the effects of drugs (pharmaco-dynamics). Their approach will also help improve the design of brain computer interfaces used to help people who are paralyzed.

"In the future, it may be possible to fluently read the processes of the brain from the EEG like one reads notes from a musical score," said Tognoli. "Our technique is already providing a unique view on brain dynamics. It shows how activity grows and dies in individual brain areas and how multiple areas engage in and disengage from working together as a coordinated team."

In addition to simple linear synchronization between brain areas, the authors describe more subtle modes of coordination during which areas may cooperate (integrate) and at the same time retain their functional specificity (segregation).

"This property of metastability falls out of our theory and is crucial for the brain," said Kelso. "The brain is a complex nonlinear dynamical system, and it needs to coordinate the activity of diverse and remotely connected parts in order to extract and communicate meaningful information."

Tognoli points out that subtle regimes of coordination are advantageous for the brain and are faster, more powerful and less energetically costly, thereby creating rich modes of interaction that surpass those of simple linear modes of coordination.

For a long time, scientists have strictly emphasized one kind of synchronization called 'inphase' or 'zero-lag synchrony' looking only at who is coordinated with whom and not observing the details of how they are coordinated. Through their research, Tognoli and Kelso have shown that the brain uses a much wider repertoire of synchronization patterns than just inphase. For example, brain areas may lock their oscillations together but keep a different phase.

This characteristic is also a key to the brain's dynamic complexity. Areas may encode distinct information when they coordinate with one phase difference or another, and the brain may finely tune itself, such as in learning, by altering the lag at which its areas coordinate rather than just switching synchrony on and off. Such a brain would have a far greater combinatorial and computational power than the old model of the 'inphase brain'. But to understand the principals at work, the lag or 'relative phase' between coupled oscillations in the brain needs to be systematically studied.

"This work lies at the intersection of neuroscience and complexity science," said Dr. Gary Perry, dean of the Charles E. Schmidt College of Science. "Drs. Kelso and Tognoli have successfully developed the specific conceptual and methodological tools needed to capture and observe these important features in empirical data. Their unique approach and findings will help to shed light on some of world's most debilitating and costly health disorders."

Florida Atlantic University

---

---

	Coordination Dynamics: Issues and Trends by Viktor K. Jirsa (Editor), J.A. Scott Kelso (Editor) 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.
	Coordination Dynamics: Issues and Trends (Understanding Complex Systems) by Viktor K. Jirsa (Editor), J.A. Scott Kelso (Editor) 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.
	Coordination: Neural, Behavioral and Social Dynamics (Understanding Complex Systems) by Armin Fuchs (Editor), Viktor K. Jirsa (Editor) One of the most striking features of Coordination Dynamics is its interdisciplinary character. The problems we are trying to solve in this field range from behavioral phenomena of interlimb coordination and coordination between stimuli and movements (perception-action tasks) through neural activation patterns that can be observed during these tasks to clinical applications and social behavior. It is not surprising that close collaboration among scientists from different fields as psychology, kinesiology, neurology and even physics are imperative to deal with the enormous difficulties we are facing when we try to understand a system as complex as the human brain. The chapters in this volume are not simply write-ups of the lectures given by the experts at the meeting but are written in a...
	The Dynamical Systems Approach to Cognition: Concepts and Empirical Paradigms Based on Self-Organization, Embodiment, and Coordination Dynamics (Studies of Nonlinear Phenomena in Life Science) by Jean-Pierre Dauwalder (Author), Wolfgang Tschacher (Author) The shared platform of the articles collected in this volume is used to advocate a dynamical systems approach to cognition. It is argued that recent developments in cognitive science towards an account of embodiment, together with the general approach of complexity theory and dynamics, have a major impact on behavioural and cognitive science. The book points out that there are two domains that follow naturally from the stance of embodiment: first, coordination dynamics is an established empirical paradigm that is best able to aid the approach; second, the obvious goal-directedness of intelligent action (i.e., intentionality) is nicely addressed in the framework of the dynamical synergetic approach.
	Fluxional Organometallic and Coordination Compounds (Physical Organometallic Chemistry) by Marcel Gielen (Editor), Rudolph Willem (Editor), Bernd Wrackmeyer (Editor) This series offers leading contributions by well-known chemists reviewing the state of the art of this wide research area. Physical organometallic chemistry aims to develop new insights and to promote novel interest and investigations applicable to organometallic chemistry.This volume focuses on several important topics on fluxionality in organometallic and coordination chemistry, reviewed by experts in each of the respective fields. It is intended to provide both authoritative concepts and stimulating ideas in order to tackle dynamics from different angles, aiming at an interdisciplinary approach. The fascinating fluxionality of metal-ligand interactions has been in the centre of interest ever since modern coordination and organometallic chemistry started, and has expanded towards...
	Dynamic Coordination in the Brain: From Neurons to Mind (Strüngmann Forum Reports) by Christoph von von der Malsburg (Editor), William A. Phillips (Editor), Wolf Singer (Editor) A fundamental shift is occurring in neuroscience and related disciplines. In the past, researchers focused on functional specialization of the brain, discovering complex processing strategies based on convergence and divergence in slowly adapting anatomical architectures. Yet for the brain to cope with ever-changing and unpredictable circumstances, it needs strategies with richer interactive short-term dynamics. Recent research has revealed ways in which the brain effectively coordinates widely distributed and specialized activities to meet the needs of the moment. This book explores these findings, examining the functions, mechanisms, and manifestations of...
	Electronic Supply Network Coordination in Intelligent and Dynamic Environments: Modeling and Implementation (Premier Reference Source) by Iraj Mahdavi (Author), Iraj Mahdavi (Editor), Shima Mohebbi (Editor), Namjae Cho (Editor) The widespread diffusion of digital infrastructure, applications, products, and services has created new challenges and opportunities for managers and corporations exposed to a dense and highly complex supply network. This complexity often requires innovative models, techniques, tools, processes, and structures.Electronic Supply Network Coordination in Intelligent and Dynamic Environments: Modeling and Implementation presents cutting-edge knowledge on scientific approaches to the management of supply networks in a highly informed global environment with abundant dynamic and uncertain challenges. This work examines how new mathematical and conceptual approaches are integrated with information technology and intelligent systems and how these models can help to improve the coordination of...
	Indian Software Industry: Business Strategy and Dynamic Co-ordination by Parthasarathi Banerjee (Author) The Indian software industry has rapidly grown over the past decade, and most of this growth has been derived from exports to the US market. This book deals with business models, particularly the way the unique software model in India has evolved. It focuses on manpower resources in the software industry and knowledge diffusion through job switching, and the resulting impacts on business strategy.
	Evaluating the coordination dynamics of handwriting [An article from: Human Movement Science] by S. Athenes (Author), I. Sallagoity (Author), P.G. Zanone (Author), J Albaret (Author) This digital document is a journal article from Human Movement Science, published by Elsevier in 2004. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser. Description: This study aims to test the hypothesis that handwriting is governed by the dynamics of non-linear coupled oscillators. Accordingly, its first goal is to identify preferred, basic graphic shapes corresponding to spontaneously stable combinations of the two frequency-locked oscillatory x-y components of the trajectories. Six participants were required to produce 26 ellipsoids of varying eccentricities and orientations presented consecutively on a graphic tablet. These shapes corresponded to a systematic...
	Interaction of neuromuscular, spatial and visual constraints on hand-foot coordination dynamics [An article from: Human Movement Science] by R. Salesse (Author), J.J. Temprado (Author), S.P. Swinnen (Author) This digital document is a journal article from Human Movement Science, published by Elsevier in 2005. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser. Description: In the present study, we investigated the contributions of motor and perceptual processes to directional constraints as observed during hand-foot coordination. Participants performed cyclical flexion-extension movements of the right hand and foot under two coordination modes: in-phase (isodirectional) and antiphase (non-isodirectional). Those tasks were performed either with full vision or no vision of the limbs. Depending on the position of the forearm (prone or supine), the coordination patterns were...