Temporal Disorder in Human Oscillatory Systems

Ludger Rensing ist Professor emeritus für Zellbiologie an der Universität Bremen. Er promovierte und habilitierte sich für das Fach Zoologie an der Universität Göttingen und arbeitete mehrere Jahre in den USA (Princeton, Harvard). Seine Arbeitsgebiete sind die Regulation von Stressgenen und Stressproteinen sowie die molekularen Mechanismen der "inneren Uhr".

Rhythms of the heart and of the nervous and endocrine system, breathing, locomotory movements, sleep, circadian rhythms and tissue cell cycles are major elements of the temporal order of man. The dynamics of these systems are characterized by changes in the properties of an oscillator, transitions from oscillatory states into chaotic or stationary states, and vice versa, coupling or uncoupling between two or more oscillators. Any deviation from the normal range to either more or less ordered states may be defined as temporal disorder. Pathological changes of temporal organization, such as tremor, epileptic seizures, Cheyne-Stokes breathing, cardiac arrhythmicities and circadian desynchronization, may be caused by small changes in the order (control) parameters. One major aspect of the symposium was the analysis of characteristic features of these temporal control systems, including nonlinear dynamics of interactions, positive, negative and mixed feedback systems, temporal delays, and their mathematical description and modelling. The ultimate goal is a better understanding of the principles of temporal organization in order to treat periodic diseases or other perturbations of "normal" dynamics in human oscillatory systems.

Temporal Disorder-Introductory Remarks By the Editors.- I Theoretical Concepts.- Coupled Oscillators in Health and Disease.- Periodic Signaling and Receptor Desensitization: From cAMP Oscillations in Dictyostelium Cells to Pulsatile Patterns of Hormone Secretion.- Oscillations and the Regulation of Spatial Order in Developing Systems.- Mixed Feedback: A Paradigm for Regular and Irregular Oscillations.- II Neural and Neuromotor Systems.- Strange Attractors in the Human Cortex.- Analysis of the Human Electroencephalogram with Methods from Nonlinear Dynamics.- Studying Temporal Order in Human CNS by Means of "Running" Frequency and Coherence Analysis.- Central Rhythmicities in Motor Control and Its Perturbances.- Neurological Oscillations: Formulation of Mathematical Control Models and Applications to Clinical Syndromes.- Quantitative Theory of Changes in Oscillatory Hand Movements- Application of Methods of Synergetics.- Investigation of Agonistic/Antagonistic Movement in Parkinson's Disease from an Ergodic Point of View.- III Heart and Respiration.- Nonlinear Dynamics, Fractals, Cardiac Physiology and Sudden Death.- Afterpotentials and Pacemaker Oscillations in an Ionic Model of Cardiac Purkinje Fibres.- Causes of Propagation Failure in Excitable Media.- Ultradian Oscillations in Human Blood Pressure: Effects of Age.- New Aspects of the Dynamics of Acute Myocardial Infarction.- Coordination in the Circulatory and Respiratory Systems.- IV Circadian Clocks.- The Autonomous Time Structure and Its Reactive Modifications in the Human Organism.- Bright Light in Work-Sleep Schedules for Shift Workers: Application of Circadian Rhythm Principles.- Disturbances of the Circadian System Due to Masking Effects.- Simulation of the Circadian Response to Time Zone Transitions bya Van der Pol Oscillator.- Circadian Rhythms and Depression.- Lithium Effects on Circadian Rhythms.- Treatment of Chronobiologic Sleep and Mood Disorders with Light: Theory and Practice.- Free-Running Melatonin Rhythms in Blind People: Phase Shifts with Melatonin and Triazolam Administration.- Effects of Pacemaker Lesions on the Temporal Organization in Mammals.- Perturbations of Cellular Circadian Rhythms by Light and Temperature.- V Ovarian Cycles.- Temporal Order and Disorder in a Model That Regulates Ovulation Number.- Index of Contributors.