Resonance in a mathematical model of baroreflex control: arterial blood pressure waves accompanying postural www.frontiersin.org June 2014 | Volume 5 | Article 234 | 7 Medow et al. Oscillatory cerebral blood flow stress

Physiol 288: R1637–R1648, 2005. First published February 17, 2005; doi:10.1152/ajpregu.00050.2004.—A mathematical model of the ar-terial baroreflex was developed and used to assess the stability of the reflex and its potential role in producing the low-frequency arterial blood pressure oscillations called Mayer waves that are commonly seen in humans and animals in response to decreased central blood volume. The model consists of an arrangement of discrete-time filters derived from published physiological studies, which is reduced to a numerical expression for the baroreflex open-loop frequency re-sponse. Model stability was assessed for two states: normal and decreased central blood volume. The state of decreased central blood volume was simulated by decreasing baroreflex parasympathetic heart rate gain and by increasing baroreflex sympathetic vaso/venomotor gains as occurs with the unloading of cardiopulmonary baroreceptors. For the normal state, the feedback system was stable by the Nyquis