Fractal physiology refers to the study of
physiological
Physiology (; ) is the scientific study of functions and mechanisms in a living system. As a sub-discipline of biology, physiology focuses on how organisms, organ systems, individual organs, cells, and biomolecules carry out the chemica ...
systems using
complexity science
A complex system is a system composed of many components which may interact with each other. Examples of complex systems are Earth's global climate, organisms, the human brain, infrastructure such as power grid, transportation or communication s ...
methods, such as
chaos measure,
entropy
Entropy is a scientific concept, as well as a measurable physical property, that is most commonly associated with a state of disorder, randomness, or uncertainty. The term and the concept are used in diverse fields, from classical thermodyna ...
, and
fractal dimension
In mathematics, more specifically in fractal geometry, a fractal dimension is a ratio providing a statistical index of complexity comparing how detail in a pattern (strictly speaking, a fractal pattern) changes with the scale at which it is meas ...
s. The underlying assumption is that biological systems are complex and exhibit non-linear patterns of activity, and that characterizing that complexity (using dedicated mathematical approaches) is useful to understand, and make inferences and predictions about the system.
Main Findings
Neurophysiology
Quantifications of the complexity of brain activity is used in the context of neuropsychiatric diseases and mental states characterization, such as schizophrenia, affective disorders, or neurodegenerative disorders. Particularly, diminished
EEG
Electroencephalography (EEG) is a method to record an electrogram of the spontaneous electrical activity of the brain. The biosignals detected by EEG have been shown to represent the postsynaptic potentials of pyramidal neurons in the neocortex ...
complexity is typically associated with increased symptomatology.
Cardiovascular systems
The complexity of
Heart Rate Variability
Heart rate variability (HRV) is the physiological phenomenon of variation in the time interval between heartbeats. It is measured by the variation in the beat-to-beat interval.
Other terms used include: "cycle length variability", "R–R variabi ...
is a useful predictor of cardiovascular health.
Software
In
Python,
NeuroKit
NeuroKit (''"nk"'') is an open source toolbox for physiological signal processing. The most recent version, ''NeuroKit2'', is written in Python and is available from the PyPI package repository. As of June 2022, the software was used in 94 scient ...
provides a comprehensive set of functions for complexity analysis of physiological data.
''AntroPy'' implements several measures to quantify the complexity of time-series.
In
R, ''TSEntropies'' provides methods to quantify the entropy. ''casnet'' implements a collection of analytic tools for studying signals recorded from complex adaptive systems.
In
MATLAB
MATLAB (an abbreviation of "MATrix LABoratory") is a proprietary multi-paradigm programming language and numeric computing environment developed by MathWorks. MATLAB allows matrix manipulations, plotting of functions and data, implementa ...
, The ''
Neurophysiological Biomarker Toolbox
The Neurophysiological Biomarker Toolbox (NBT) is an open source MATLAB toolbox for the computation and integration of neurophysiological biomarkers (e.g., biomarkers based on EEG or MEG recordings). The NBT toolbox has so far been used in s ...
'' (NBT) allows the computation of
Detrended fluctuation analysis In stochastic processes, chaos theory and time series analysis, detrended fluctuation analysis (DFA) is a method for determining the statistical self-affinity of a signal. It is useful for analysing time series that appear to be long-memory proces ...
. ''EZ Entropy'' implements the entropy analysis of physiological time-series.
See also
*
Fractal dimension
In mathematics, more specifically in fractal geometry, a fractal dimension is a ratio providing a statistical index of complexity comparing how detail in a pattern (strictly speaking, a fractal pattern) changes with the scale at which it is meas ...
*
Entropy
Entropy is a scientific concept, as well as a measurable physical property, that is most commonly associated with a state of disorder, randomness, or uncertainty. The term and the concept are used in diverse fields, from classical thermodyna ...
*
Complex system
A complex system is a system composed of many components which may interact with each other. Examples of complex systems are Earth's global climate, organisms, the human brain, infrastructure such as power grid, transportation or communicatio ...
References
Fractals
Physiology
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