Title: Understanding entrainment of circadian systems using one-dimensional maps

Speaker: Prof. Amitabha Bose, New Jersey Institute of Technology, Newark

Abstract: A central feature of circadian systems is their response to an external, pacemaking 24 hour light-dark (LD) drive which typically leads to entrainment of circadian oscillator. Of particular interest is determining the time needed to entrain an oscillator due to changes in the light-dark input. There are also several naturally arising situations in which a circadian system is incapable of entrainment, perhaps due to abnormal intrinsic properties of the oscillators. In this talk, we will use entrainment maps to describe two scenarios: 1) the transient dynamics leading to a normal fixed phase relationship between LD forcing and oscillator such as during jet lag; and 2) the use of Bright Light Therapy to correct for non-24 hour sleep-wake disorder. The mathematical and computational methods used to study these problems revolve around finding stable limit cycle solutions of the governing equations and it is the reduction of this study to a one-dimensional framework that will be the focus of the talk.