Europhys. Lett, 43 (4), pp. 363-368 (1998)
Stochastic feedback and the regulation
of biological rhythms
P. Ch. Ivanov 1, L. A. Nunes Amaral 1,2, A. L. Goldberger 3 and H. E. Stanley 1
1 Center for Polymer Studies and Department of Physics,
Boston, MA 02215, USA
2 Department of Physics, Massachusetts Institute of Technology
Cambridge, MA 02139, USA
3 Cardiovascular Division, Harvard Medical School
Beth Israel Hospital, Boston, MA 02215, USA
(received 12 May 1998; accepted in final form 26 June 1998)
PACS. 02.50Ey - Stochastic processes.
PACS. 05.40 - Fluctuation phenomena, random processes, and Brownian motion.
PACS. 05.45 - Theory and models of chaotic systems.
We propose a general approach to the question of how biological rhythms spontaneously self-regulate, based on the concept of "stochastic feedback''. We illustrate this approach by considering at a coarse-grained level the neuroautonomic regulation of the heart rate. The model generates complex dynamics and successfully accounts for key characteristics of cardiac variability, including the 1/f power spectrum, the functional form and scaling of the distribution of variations, and correlations in the Fourier phases indicating nonlinear dynamics.