Temporal Correlation in Phrenic Neural Activity
Neural activity which gives rise to eupnea fluctuates in a complex manner. Apparently “noisy” variations in activity of the phrenic nerve may display a fractal scaling relationship. Fractal scaling in eupnea is the consequence of physical and chemical processes acting over short time scales at the cellular level, and which are correlated with similar processes acting simultaneously over longer time scales. Specifically, variations in phrenic neural bursts may not be independent random fluctuations or entirely due to short-range influences4, but may exhibit temporal correlation indicative of fractal scaling. West and Deering20 have demonstrated that fractal processes are essentially unresponsive to error and very tolerant of variability in the physiological environment. In this view, eupnea with its concomitant stability to error from a broad spectrum of inputs must have the error-tolerant properties of fractals.
KeywordsPower Spectral Density Temporal Correlation Phrenic Nerve Detrended Fluctuation Analysis Fractal Scaling
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- 2.Beagle, J. L., B. Hoop, and H. Kazemi. Phrenic nerve response to glutamate antagonist microinjection in the ventral medulla. In: Advances in Control and Modeling of Ventilation, edited by R. Hughson, D. A. Cunningham, and J. Duffin., New York: Plenum, 1998, (this volume).Google Scholar
- 6.Feder, J. Fractals. New York: Plenum, 1988, pp. 180–181.Google Scholar
- 16.Szeto, H. H, P. Y. Cheng, J. A. Decena, Y. Cheng, D. Wu, and G. Dwyer. Fractal properties in fetal breathing dynamics. Am. J. Physiol. 263: R141–R147, 1992.Google Scholar