Abstract:

The human organism is an integrated network where complex physiological systems, each with its own regulatory mechanisms, continuously interact, and where failure of one system can trigger a breakdown of the entire network. Identifying and quantifying dynamical networks of diverse systems with different types of interactions is a challenge. Through the prism of concepts and approaches originating in statistical physics and nonlinear dynamics, we will present basic characteristics of individual organ systems, distinct forms of pairwise coupling between systems, and a new framework to identify and quantify networks of interactions among diverse organ systems. We find that each physiological state is characterized by a specific network structure, demonstrating a robust interplay between network topology and function. Across physiological states, the network undergoes topological transitions associated with hierarchical reorganization of physiological interactions on time scales of seconds, indicating high network flexibility in response to perturbations. The proposed system-wide integrative approach lays the foundations of a new interdisciplinary field, Network Physiology. 

Biosketch: 

Prof. Plamen Ch. Ivanov (PhD, DSc) is Director of the Keck Laboratory for Network Physiology at Boston University, Associate Physiologist at the Division of Sleep Medicine, Brigham and Women's Hospital, and Lecturer in Medicine at Harvard Medical School. He has pioneered innovative ways to study physiologic systems, developing concepts and methods from statistical physics and nonlinear dynamics. He has investigated cardiac and respiratory dynamics, sleep-stage transitions, circadian rhythms, locomotion and brain dynamics, and has uncovered basic laws of physiologic regulation. His discoveries are featured in media reports, including New Scientist, Nature Science Update, Washington Post, Science News, Boston Globe, Physics World. He is Elected Fellow of the American Physical Society, and recipient of the Sustained Research Excellence Award at Harvard Medical School, the Georgi Nadjakov Medal, the Pythagoras (Pitagor) Prize and the W. M. Keck Foundation Award.