Breathing during REM and non-REM sleep: correlated versus uncorrelated behaviour

Phase transitions in physiologic coupling

“…Considering the degree of phase synchronization as an order parameter characterizing the system, our observations of a continuous decline of CRPS from DS and LS to REM and wake, which is also paralleled by an increase in the long-range power-law correlation exponents of the cardiac and respiratory dynamics (9,(14)(15)(16), is reminiscent of a secondorder phase transition in physical systems.…”

“…Empirical studies have reported a strong variation in linear and nonlinear characteristics in both cardiac and respiratory dynamics with the sleep-wake cycle (9), across circadian phases (10-12) and sleep-stage transitions (13)(14)(15)(16), indicating significant changes in the regulatory mechanisms with transitions across physiological states. Thus, we hypothesize that cardiorespiratory coupling may undergo phase transitions with transitions across physiological states.…”

Scaling law of diffusivity generated by a noisy telegraph signal with fractal intermittency

“…The second one is a Poisson noise, i.e., a sequence of events with Poisson statistics, whish is superposed to the complex component. In analogy with the concept of white noise added to monoor multi-fractal signals, which was discussed by many authors [55,56,57,58,59,60], the Poisson noise can encode the effects of the external environment, or it can represent the source of errors in a statistical algorithm for data analysis, or it can be even a sort of residual of the cooperative dynamics, which, in this case, would generate both self-organization and uncorrelated noise. It is not always clear a priori if the noise component in a complex signal is due to the external environment or a sort of residual manifestation of non-linear interactions, which determine also the emergence of cooperative behavior.…”

“…Following this interpretation, the role of added noise in complex systems has been extensively investigated by many authors, as it can affect the observed scaling properties [55,53,15,56,57,58,59,60]. In particular, many authors have studied the effect of added noise on monofractal and multifractal signals.…”

“…Further, the presence of short-term noise can affect the calculation of long-range correlations [55,58] and of intermittency features [53,15]. Recently, the presence of added Gaussian noise, white or exponentially correlated, has been recognized to play a crucial role for the interpretation of single particle tracking of biomolecules in the cell [59].…”