Dr. C. Frank Starmer
Duke - NUS Graduate Medical School Singapore
Simple mechanisms often underly apparently complex behavior. My interest in non-linear systems started with a course during my graduate program. I was impressed that small changes ofter dramatically altered a system's response. While exploring mechanisms by which drugs bind to membrane ion channels, I realized that many complex cardiac arrhythmias are associated with simple alterations of membrane electrical properties and display very complex spatial and temporal behavior. Exploring drug effects with simple models of a cardiac cell qualitatively displayed many of the features of clinical cardiac arrhythmias.
Valentin Krinsky introduced me to the concept of generic properties of a nonlinear dynamic system and used the Fitzhugh-Nagumo model as a minimally complex representation of a cardiac cell. I slowly realized that all the complexity of a biological system need not be reflected in a mathematical or computational model. It was only necessary to include those model components that provided the basis of one or more of Krinsky's generic properties. Vadim Biktashev spent part of each day in Krinsky's lab and provided additional insights into generic properties of excitable systmes.
These two articles explore generic properties of excitable systems: successful propagation secondary to disturbing an excitable medium at equilibrium and creating wave breaks by violating the requirements of sustained propagation.