|Dr. Ronny Bartsch|
We investigate how diverse physiologic systems in the human organism dynamically interact and collectively behave to produce distinct physiologic states and functions. This is a fundamental question in the new interdisciplinary field of Network Physiology and has not been previously explored. Here, we introduce the novel concept of time delay stability (TDS) to probe interactions among diverse systems. The TDS method determines the time delay with which modulations/bursts in the output dynamics of a given system are consistently followed by corresponding modulations in the signal output of other systems. Utilizing TDS, we distinguish between stable and unstable interactions, characterize coupling strength and identify a physiological network. We find that the network undergoes transitions with changes in physiological state, demonstrating a robust interplay between network and function. These empirical investigations shed new light on the mechanisms of organ interactions and establish a first association between patterns of physiological network interactions and specific physiologic states.