Power spectra and cooperativity of a calcium-regulated cation channel

McGeoch, Malcolm W.; McGeoch, Julie E. M.

doi:10.1016/s0006-3495(94)80747-7

Cited by 21 publications

(22 citation statements)

References 14 publications

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“…It has been observed that the Fourier transform of ionic current through BK channels is not a Lorentzian curve as would be expected for statistically independent channels but exhibits a power law with an exponent between -1 and -2 [47]. The 1/f flicker noise can be caused due to various reasons; co-operativity between channels [48], second-order conformation change in the channel leading to incomplete closure of the pore or obstruction of ion passage across the channel [49,50]. Whether these observations apply to other classes of voltage-gated ion channels remains unclear [51].…”

Section: Discussionmentioning

confidence: 99%

Comparison of Langevin and Markov channel noise models for neuronal signal generation

2010

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Section: Discussionmentioning

confidence: 99%

Comparison of Langevin and Markov channel noise models for neuronal signal generation

2010

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“…Possible candidates include ionic channels, in which fractal patterns of channel gating in single-channel recordings were observed and mathematical models of channel gating accounting for this property were formulated. 26,27 Moreover, electrophysiological studies showed the presence of fractal characteristics in the oscillations of the membrane potential. 28 Also, it was shown that, while isolated cardiac cells beat stochastically, fractal patterns of activity establish when a large number of cells are electrically coupled and synchronize.…”

Section: Intrinsic Power-law Behavior: Possible Mechanismsmentioning

confidence: 99%

Power-Law Behavior of Beat-Rate Variability in Monolayer Cultures of Neonatal Rat Ventricular Myocytes

Kučera

Heuschkel

Renaud

et al. 2000

Circulation Research

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Abstract-It is known that extracardiac factors (nervous, humoral, and hemodynamic) participate in the power-law behavior of heart-rate variability. To assess whether intrinsic properties of cardiac tissue might also be involved, beat-rate variability was studied in spontaneously beating cell cultures devoid of extracardiac influences. Extracellular electrograms were recorded from monolayer cultures of neonatal rat ventricular myocytes under stable incubating conditions for up to 9 hours. The beat-rate time series of these recordings were examined in terms of their Fourier spectra and their Hurst scaling exponents. A non-0 Hurst exponent was found in 21 of 22 preparations (0.29Ϯ0.09; range, 0.11 to 0.45), indicating the presence of fractal self-similarity in the beat-rate time series. The same preparations exhibited power-law behavior of the power spectra with a power-law exponent of Ϫ1.36Ϯ0.24 (range, Ϫ1.04 to Ϫ1.96) in the frequency range of 0.001 to 1 Hz. Furthermore, it was found that the power-law exponent was nonstationary over time. These results indicate that the power-law behavior of heart-rate variability is determined not only by extracardiac influences but also by components intrinsic to cardiac tissue. Furthermore, the presence of power-law behavior in monolayer cultures of cardiomyocytes suggests that beat-rate variability might be determined by the complex nonlinear dynamics of processes occurring at the level of the cellular network, eg, interactions among a large number of cell oscillators or metabolic regulatory systems. (Circ Res. 2000;86:1140-1145.)Key Words: heart-rate variability Ⅲ cardiac cell cultures Ⅲ physiology Ⅲ extracellular recording B eat-to-beat variations in cardiac cycle length have received increasing attention, because their characteristics may be used for the assessment and follow-up of various cardiovascular derangements and for risk stratification in the course of cardiac disease, including prediction of arrhythmias in cardiac patients. 1,2 Spectral analysis of beat-rate time series reveals periodic components in heart-rate variability (HRV). 3 In humans, 2 major components are present at frequencies around 0.1 Hz (low-frequency [LF] component) and around 0.25 Hz (highfrequency [HF] component). 4 It is well established that these periodic components are linked to breathing and blood pressure control and that they are mediated by the autonomic nervous system 5,6 and by endocrine influences. 3 However, the analysis of long-term recordings (ie, 24-hour Holter electrocardiograms) indicates that Ͼ95% of the spectral power of HRV is concentrated at frequencies below LF. 1 At these very low frequencies, the spectrum follows a power-law behavior; ie, the intensity of the power spectrum is a power function of frequency. The exponent of this power-law is close to Ϫ1 in healthy human subjects. 7 Several studies showed that this exponent is different after myocardial infarction 8,9 or cardiac transplantation 9 and that the characterization of power-law behavior can yield potent estimate...

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“…Calcium has been implicated in the neurochemistry of synaptic signal transduction and memory formation for some time (10, 60–63). This may turn out to helpful when one attempts to link mental processes to actual molecular processing.…”

Section: From Recurrent Network To Molecular Substrates Of Consciousmentioning

confidence: 99%

“…In an Ising model, collective behavior of interacting parts such as magnetic particles (spin up or down) or neurons (on or off) is based on simple neighboring rules (ferromagnetic/activating, anti-ferromagnetic/inhibiting, or non-interacting). Curiously, the Ising model is applicable to the opening state of ion channels (60, 69–70), which implies that the fractal neural network activity can be mapped onto the collective opening of ion channels in the dendritic tree. Therefore, fractality is preserved when the pattern of activity nodes in dendritic trees is mapped onto the opening/closing distribution of ion channels in a hexagonal lattice (Figs.…”

Section: From Recurrent Network To Molecular Substrates Of Consciousmentioning

confidence: 99%

Introduction to the Fractality Principle of Consciousness and the Sentyon Postulate

Bieberich¹

2011

Cogn Comput

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Recently, consciousness research has gained much attention. Indeed, the question at stake is significant: why is the brain not just a computing device, but generates a perception from within? Ambitious endeavors trying to simulate the entire human brain assume that the algorithm will do the trick: as soon as we assemble the brain in a computer and increase the number of operations per time, consciousness will emerge by itself. I disagree with this simplistic representation. My argument emerges from the “atomism paradox”: the irreducible space of the consciously perceived world, the endospace is incompatible with the reducible and decomposable architecture of the brain or a computer. I will first discuss the fundamental challenges in current consciousness models and then propose a new model based on the fractality principle: “the whole is in each of its parts”. This new model copes with the atomism paradox by implementing an iterative mapping of information from higher order brain structures to smaller scales on the cellular and molecular level, which I will refer to as “fractalization”. This information fractalization gives rise to a new form of matter that is conscious (“bright matter”). Bright matter is composed of conscious particles or units named “sentyons”. The internal fractality of these sentyons will close a loop (the “psychic loop”) in a recurrent fractal neural network (RFNN) that allows for continuous and complete information transformation and sharing between higher order brain structures and the endpoint substrate of consciousness at the molecular level.

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Power spectra and cooperativity of a calcium-regulated cation channel

Cited by 21 publications

References 14 publications

Comparison of Langevin and Markov channel noise models for neuronal signal generation

Comparison of Langevin and Markov channel noise models for neuronal signal generation

Power-Law Behavior of Beat-Rate Variability in Monolayer Cultures of Neonatal Rat Ventricular Myocytes

Introduction to the Fractality Principle of Consciousness and the Sentyon Postulate

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