Complex Synchronization in Physiological Systems

Kurths, Juergen

Synchronization, discovered by Huygens in the 17th century, is a universal phenomenon that occurs when two or more nonlinear oscillators are coupled. It is observed in many fields of science and is widely applied in engineering. The notion of synchronization has been often used to analyze the interaction between physiological systems, but these studies have been restricted to almost periodic rhythms. We have recently found the new phenomenon of phase synchronization in coupled chaotic systems, i.e. the phases are synchronized, whereas the amplitudes remain nearly uncorrelated. This finding is used to develop a technique to analyze irregular nonstationary bivariate data. This way we detect a hidden synchrony of heart beat and respiration. We also identify regions in the cortex which are phase synchronized with the tremor of Parkinson patients.