The fractal organization of ultradian rhythms in avian behavior

Abstract

Living systems exhibit non-randomly organized biochemical, physiological, and behavioral processes that follow distinctive patterns. In particular, animal behavior displays both fractal dynamics and periodic rhythms yet the relationship between these two dynamic regimens remain unexplored. Herein we studied locomotor time series of visually isolated Japanese quails sampled every 0.5 s during 6.5 days (>106 data points). These high-resolution, week-long, time series enabled simultaneous evaluation of ultradian rhythms as well as fractal organization according to six different analytical methods that included Power Spectrum, Enright, Empirical Mode Decomposition, Wavelet, and Detrended Fluctuation analyses. Time series analyses showed that all birds exhibit circadian rhythms. Although interindividual differences were detected, animals presented ultradian behavioral rhythms of 12, 8, 6, 4.8, 4 h and/or lower and, irrespective of visual isolation, synchronization between these ultradian rhythms was observed. Moreover, all birds presented similar overall fractal dynamics (for scales ∼30 s to >4.4 h). This is the first demonstration that avian behavior presents fractal organization that predominates at shorter time scales and coexists with synchronized ultradian rhythms. This chronobiological pattern is advantageous for keeping the organism’s endogenous rhythms in phase with internal and environmental periodicities, notably the feeding, light-dark and sleep-wake cycles.

C. elegans episodic swimming is driven by multifractal kinetics

“…A scale-free distribution of actively-moving and inactive residence times has been reported for episodic Drosophila behavior; modeling suggested that the scale-free nature of these residence times contributes to maximizing the food exploitation area while optimizing food intake time 8 . Previous analyses have shown long-range temporal correlations in scale-free properties of the behaviors of many species, including fractal (but not multifractal) analysis of C. elegans crawling 6 , 7 , 9 – 12 . The fractal nature of C. elegans crawling in agar 9 is consistent with our long-range memory and clusterization finding.…”

Temporal metabolic partitioning of the yeast and protist cellular networks: the cell is a global scale-invariant (fractal or self-similar) multioscillator

“…121 The research at the Johns Hopkins Group and at the NIH Institute on Aging lays a firm foundation and opens new windows for diagnostic monitoring as pioneered and elaborated by Chance and his coworkers. 122,123 Thus, this iterative approach of experimental and computational interrogation of complex biological systems (systems biology) has gained much traction recently, is under continual development, and has been applied throughout chronobiology, 104,[124][125][126][127] bioengineering, and bioscience. Further technical details are provided in publications cited in the reference section.…”

C. elegansepisodic swimming is driven by multifractal kinetics

“…A scale-free distribution of actively-moving and inactive residence times has been reported for episodic Drosophila behavior 9 ; modeling suggested that the scale-free nature of these residence times contributes to maximizing the food exploitation area while optimizing food intake time. Previous analyses have shown long-range temporal correlations in scale-free properties of the behaviors of many species, including fractal (but not multifractal) analysis of C. elegans crawling 7,8,10–13 . The fractal nature of C. elegans crawling in agar (Alves et al, 2017) is consistent with our long-range memory and clusterization finding.…”