juan carlos Letelier - Academia.edu (original) (raw)
Papers by juan carlos Letelier
Here we introduce a new approach for Gaussianity testing using the envelope of a signal. The coef... more Here we introduce a new approach for Gaussianity testing using the envelope of a signal. The coefficient of variation (std mean) of the envelope (CVE) of zero-mean Gaussian noise is a universal constant equal to m = (4 − π)/π ≈ 0.523. Thus, for any signal the result CVE = m can be used as a fingerprint to assess Gaussianity. Interestingly, the CVE is also unique for uniform noise time series or low density Filtered Poisson Processes. Here we summarize the mathematics and computer methods behind using the CVE for Gaussianity testing in time series. In particular, we describe how to perform Gaussianity testing in a step-by-step fashion for experimental data using the Hilbert transform, showing that the sampling rate as well as the duration and the filtering of the data stream affect the analysis. Additionally, through the use of the Fourier transform phase randomization, we reveal the interconnections among CVE, Gaussianity and temporal modulation profiles. Furthermore, we use the CVE to assess the degree of synchronization in Kuramoto and Matthews-Mirollo-Strogatz models and show that CVE is relevant to the study of coupled oscillators systems. CVE Gaussianity testing provides a new tool for signal classification.
There are deep underlying similarities between Rosen's (M,R) systems as a definition of life and ... more There are deep underlying similarities between Rosen's (M,R) systems as a definition of life and the RAF sets (Reflexive Autocatalytic systems generated by a Food source) introduced by Hordijk and Steel as a way of analyzing autocatalytic sets of reactions. Using RAF concepts we have systematically explored the set of possible small idealized metabolic networks, searching for instances of (M,R) systems. This exhaustive search has shown that the central requirement of Rosen's framework, unicity of , becomes harder and harder to obtain as the network grows in size. In addition, we give an expression for operators , and in terms of RAF sets.
Artificial Life IX, 2004
The work of Robert Rosen, related to metabolic networks called (MR) systems is reviewed and clari... more The work of Robert Rosen, related to metabolic networks called (MR) systems is reviewed and clarified. We study the algebraic formulation of (M,R) systems particularly the mapping , which encapsulates Rosen's solution to the problem of metabolic closure and infinite regress. We construct an arithmetical example of an (MR) system and also an (MR) system based on a three-step minimal metabolism.
In 1973, in the middle of rather unfortunate political events, two Chilean biologists, Humberto M... more In 1973, in the middle of rather unfortunate political events, two Chilean biologists, Humberto Maturana and Francisco Varela, introduced the concept of Autopoietic
Biological Research, 1995
The self-organization of neurotopies where neural connections follow Hebbian dynamics is framed i... more The self-organization of neurotopies where neural connections follow Hebbian dynamics is framed in terms of linear operator theory. A general and exact equation describing the time evolution of the overall synaptic strength connecting two neural laminae is derived. This linear matricial equation, which is similar to the equations used to describe oscillating systems in physics, is modified by the introduction of non-linear terms, in order to capture self-organizing (or auto-organizing) processes. The behavior of a simple and small system, that contains a non-linearity that mimics a metabolic constraint, is analyzed by computer simulations. The emergence of a simple "order" (or degree of organization) in this low-dimensionality model system is discussed.
Biological research, 1995
We propose that to understand the biological and neurophysiological processes that give rise to h... more We propose that to understand the biological and neurophysiological processes that give rise to human mental phenomena it is necessary to consider them as behavioral relational phenomena. In particular, we propose that: a) these phenomena take place in the relational manner of living that human language constitutes, and b) that they arise as recursive operations in such behavioral domain. Accordingly, we maintain that these phenomena do not take place in the brain, nor are they the result of a unique operation of the human brain, but arise with the participation of the brain as it generates the behavioral relational dynamics that constitutes language.
... Computing with Autopoietic and (M, R) System Juan Carlos Letelier, Gonzalo Mann, Jorge Mpodoz... more ... Computing with Autopoietic and (M, R) System Juan Carlos Letelier, Gonzalo Mann, Jorge Mpodozis and Jorge Soto-Andrade Departamento de ... Instead of having a replication map DQ APs have an iteration map that defines the internal dynamics through a recursive procedure. ...
Journal of Neuroscience, 2006
From the many attempts to produce a conceptual framework for the organization of living systems, ... more From the many attempts to produce a conceptual framework for the organization of living systems, the notions of (M,R) systems and Autopoiesis stand out for their rigor, their presupposition of the circularity of metabolism, and the new epistemologies that they imply. From their inceptions, these two notions have been essentially disconnected because each has defined its own language and tools. Here we demonstrate the existence of a deep conceptual link between (M,R) systems and Autopoietic systems. This relationship permits us to posit that Autopoietic systems, which have been advanced as capturing the central aspects of living systems, are a subset of (M,R) systems. This result, in conjunction with previous theorems proved by Rosen, can be used to outline a demonstration that the operation of Autopoietic systems cannot be simulated by Turing machines. This powerful result shows the potential of linking these two models. Finally, we suggest that the formalism of (M,R) systems could ...
The origin of the human alpha rhythm has been a matter of debate since Lord Adrian attributed it ... more The origin of the human alpha rhythm has been a matter of debate since Lord Adrian attributed it to synchronous neural populations in the occipital cortex. While some authors have pointed out the Gaussian characteristics of the alpha rhythm, their results have been repeatedly disregarded in favor of Adrian’s interpretation; even though the first EEG Gaussianity reports can be traced back to the origins of EEG. Here we revisit this problem using the envelope analysis — a method that relies on the fact that the coefficient of variation of the envelope (CVE) for continuous-time zero-mean Gaussian white noise (as well as for any filtered sub-band) is equal to , thus making the CVE a fingerprint for Gaussianity. As a consequence, any significant deviation from Gaussianity is linked to synchronous neural dynamics. Low-CVE signals come from phase-locking dynamics, while mid-CVE signals constitute Gaussian noise. High-CVE signals have been linked to unsteady dynamics in populations of nonli...
espanolEntrevista realizada por un sociologo y cineasta a un especialista en la neurobiologia de ... more espanolEntrevista realizada por un sociologo y cineasta a un especialista en la neurobiologia de la percepcion visual, la que busca construir transdiciplinariamente una descripcion sobre los problemas de la cognicion y percepcion del 3D. En ella el entrevistador remite al arte y los desafios de la tecnologia 3D y su audiencia, mientras que las respuestas son planteadas desde el punto de vista de lo que la neurociencia puede aportar al arte. EnglishInterview by a sociologist and filmmaker to a specialist in the neurobiology of visual perception, looking in transdisciplinary form build a description of the problems of cognition and perception of 3D. Here the interviewer refers to the art and challenges of 3D technology and its audience, while responses are raised from the point of view of what neuroscience can contribute to art.
From the many attempts to produce a conceptual framework for the organization of living systems, ... more From the many attempts to produce a conceptual framework for the organization of living systems, the notions of (M,R) systems and Autopoiesis stand out for their rigor, their presupposition of the circularity of metabolism, and the new epistemologies that they imply. From their inceptions, these two notions have been essentially disconnected because each has defined its own language and tools. Here we demonstrate the existence of a deep conceptual link between (M,R) systems and Autopoietic systems. But in order to prove such connection we will have to explain with detail the conceptual framework of both models. The case of (M,R) systems is rather difficult as its structure was never explained in detail by Rosen. We will give our understanding of Rosen model (see Organizational invariance and metabolic closure: analysis in terms of (M,R) systems. Journal of Theoretical Biology 238 (4): 949-961. (2006)). Also the history of the notion of Autopoietic systems (created by Humberto Matura...
European Journal of Neuroscience, 2015
Metabolism-repair systems ((M,R)) were introduced by Robert Rosen as an abstract representation o... more Metabolism-repair systems ((M,R)) were introduced by Robert Rosen as an abstract representation of cell metabolic activity. The representation was obtained in the context of Relational Biology, which means that organization prevails over the physico- chemical structure of the components involved. This fact was determinant for algebraically formalizing (M,R) systems using the theory of categories. Two elements are considered in the construction of (M,R) systems: the metabolic activity (M) and the repair functions (R) acting on the unities of the metabolic process. The metabolic system M is considered as an input-output system. In the categorical representation, inputs and outputs are the objects of the category and the processes connecting these elements are represented by the arrows of the category. Autopoiesis is a concept developed by Humberto Maturana and Francisco Varela in order to analyze the nature of living systems. It takes into account the circular organization of metaboli...
Journal of Comparative Neurology, 2015
Here we introduce a new approach for Gaussianity testing using the envelope of a signal. The coef... more Here we introduce a new approach for Gaussianity testing using the envelope of a signal. The coefficient of variation (std mean) of the envelope (CVE) of zero-mean Gaussian noise is a universal constant equal to m = (4 − π)/π ≈ 0.523. Thus, for any signal the result CVE = m can be used as a fingerprint to assess Gaussianity. Interestingly, the CVE is also unique for uniform noise time series or low density Filtered Poisson Processes. Here we summarize the mathematics and computer methods behind using the CVE for Gaussianity testing in time series. In particular, we describe how to perform Gaussianity testing in a step-by-step fashion for experimental data using the Hilbert transform, showing that the sampling rate as well as the duration and the filtering of the data stream affect the analysis. Additionally, through the use of the Fourier transform phase randomization, we reveal the interconnections among CVE, Gaussianity and temporal modulation profiles. Furthermore, we use the CVE to assess the degree of synchronization in Kuramoto and Matthews-Mirollo-Strogatz models and show that CVE is relevant to the study of coupled oscillators systems. CVE Gaussianity testing provides a new tool for signal classification.
There are deep underlying similarities between Rosen's (M,R) systems as a definition of life and ... more There are deep underlying similarities between Rosen's (M,R) systems as a definition of life and the RAF sets (Reflexive Autocatalytic systems generated by a Food source) introduced by Hordijk and Steel as a way of analyzing autocatalytic sets of reactions. Using RAF concepts we have systematically explored the set of possible small idealized metabolic networks, searching for instances of (M,R) systems. This exhaustive search has shown that the central requirement of Rosen's framework, unicity of , becomes harder and harder to obtain as the network grows in size. In addition, we give an expression for operators , and in terms of RAF sets.
Artificial Life IX, 2004
The work of Robert Rosen, related to metabolic networks called (MR) systems is reviewed and clari... more The work of Robert Rosen, related to metabolic networks called (MR) systems is reviewed and clarified. We study the algebraic formulation of (M,R) systems particularly the mapping , which encapsulates Rosen's solution to the problem of metabolic closure and infinite regress. We construct an arithmetical example of an (MR) system and also an (MR) system based on a three-step minimal metabolism.
In 1973, in the middle of rather unfortunate political events, two Chilean biologists, Humberto M... more In 1973, in the middle of rather unfortunate political events, two Chilean biologists, Humberto Maturana and Francisco Varela, introduced the concept of Autopoietic
Biological Research, 1995
The self-organization of neurotopies where neural connections follow Hebbian dynamics is framed i... more The self-organization of neurotopies where neural connections follow Hebbian dynamics is framed in terms of linear operator theory. A general and exact equation describing the time evolution of the overall synaptic strength connecting two neural laminae is derived. This linear matricial equation, which is similar to the equations used to describe oscillating systems in physics, is modified by the introduction of non-linear terms, in order to capture self-organizing (or auto-organizing) processes. The behavior of a simple and small system, that contains a non-linearity that mimics a metabolic constraint, is analyzed by computer simulations. The emergence of a simple "order" (or degree of organization) in this low-dimensionality model system is discussed.
Biological research, 1995
We propose that to understand the biological and neurophysiological processes that give rise to h... more We propose that to understand the biological and neurophysiological processes that give rise to human mental phenomena it is necessary to consider them as behavioral relational phenomena. In particular, we propose that: a) these phenomena take place in the relational manner of living that human language constitutes, and b) that they arise as recursive operations in such behavioral domain. Accordingly, we maintain that these phenomena do not take place in the brain, nor are they the result of a unique operation of the human brain, but arise with the participation of the brain as it generates the behavioral relational dynamics that constitutes language.
... Computing with Autopoietic and (M, R) System Juan Carlos Letelier, Gonzalo Mann, Jorge Mpodoz... more ... Computing with Autopoietic and (M, R) System Juan Carlos Letelier, Gonzalo Mann, Jorge Mpodozis and Jorge Soto-Andrade Departamento de ... Instead of having a replication map DQ APs have an iteration map that defines the internal dynamics through a recursive procedure. ...
Journal of Neuroscience, 2006
From the many attempts to produce a conceptual framework for the organization of living systems, ... more From the many attempts to produce a conceptual framework for the organization of living systems, the notions of (M,R) systems and Autopoiesis stand out for their rigor, their presupposition of the circularity of metabolism, and the new epistemologies that they imply. From their inceptions, these two notions have been essentially disconnected because each has defined its own language and tools. Here we demonstrate the existence of a deep conceptual link between (M,R) systems and Autopoietic systems. This relationship permits us to posit that Autopoietic systems, which have been advanced as capturing the central aspects of living systems, are a subset of (M,R) systems. This result, in conjunction with previous theorems proved by Rosen, can be used to outline a demonstration that the operation of Autopoietic systems cannot be simulated by Turing machines. This powerful result shows the potential of linking these two models. Finally, we suggest that the formalism of (M,R) systems could ...
The origin of the human alpha rhythm has been a matter of debate since Lord Adrian attributed it ... more The origin of the human alpha rhythm has been a matter of debate since Lord Adrian attributed it to synchronous neural populations in the occipital cortex. While some authors have pointed out the Gaussian characteristics of the alpha rhythm, their results have been repeatedly disregarded in favor of Adrian’s interpretation; even though the first EEG Gaussianity reports can be traced back to the origins of EEG. Here we revisit this problem using the envelope analysis — a method that relies on the fact that the coefficient of variation of the envelope (CVE) for continuous-time zero-mean Gaussian white noise (as well as for any filtered sub-band) is equal to , thus making the CVE a fingerprint for Gaussianity. As a consequence, any significant deviation from Gaussianity is linked to synchronous neural dynamics. Low-CVE signals come from phase-locking dynamics, while mid-CVE signals constitute Gaussian noise. High-CVE signals have been linked to unsteady dynamics in populations of nonli...
espanolEntrevista realizada por un sociologo y cineasta a un especialista en la neurobiologia de ... more espanolEntrevista realizada por un sociologo y cineasta a un especialista en la neurobiologia de la percepcion visual, la que busca construir transdiciplinariamente una descripcion sobre los problemas de la cognicion y percepcion del 3D. En ella el entrevistador remite al arte y los desafios de la tecnologia 3D y su audiencia, mientras que las respuestas son planteadas desde el punto de vista de lo que la neurociencia puede aportar al arte. EnglishInterview by a sociologist and filmmaker to a specialist in the neurobiology of visual perception, looking in transdisciplinary form build a description of the problems of cognition and perception of 3D. Here the interviewer refers to the art and challenges of 3D technology and its audience, while responses are raised from the point of view of what neuroscience can contribute to art.
From the many attempts to produce a conceptual framework for the organization of living systems, ... more From the many attempts to produce a conceptual framework for the organization of living systems, the notions of (M,R) systems and Autopoiesis stand out for their rigor, their presupposition of the circularity of metabolism, and the new epistemologies that they imply. From their inceptions, these two notions have been essentially disconnected because each has defined its own language and tools. Here we demonstrate the existence of a deep conceptual link between (M,R) systems and Autopoietic systems. But in order to prove such connection we will have to explain with detail the conceptual framework of both models. The case of (M,R) systems is rather difficult as its structure was never explained in detail by Rosen. We will give our understanding of Rosen model (see Organizational invariance and metabolic closure: analysis in terms of (M,R) systems. Journal of Theoretical Biology 238 (4): 949-961. (2006)). Also the history of the notion of Autopoietic systems (created by Humberto Matura...
European Journal of Neuroscience, 2015
Metabolism-repair systems ((M,R)) were introduced by Robert Rosen as an abstract representation o... more Metabolism-repair systems ((M,R)) were introduced by Robert Rosen as an abstract representation of cell metabolic activity. The representation was obtained in the context of Relational Biology, which means that organization prevails over the physico- chemical structure of the components involved. This fact was determinant for algebraically formalizing (M,R) systems using the theory of categories. Two elements are considered in the construction of (M,R) systems: the metabolic activity (M) and the repair functions (R) acting on the unities of the metabolic process. The metabolic system M is considered as an input-output system. In the categorical representation, inputs and outputs are the objects of the category and the processes connecting these elements are represented by the arrows of the category. Autopoiesis is a concept developed by Humberto Maturana and Francisco Varela in order to analyze the nature of living systems. It takes into account the circular organization of metaboli...
Journal of Comparative Neurology, 2015