267 research outputs found
Thermodynamics of exponential Kolmogorov-Nagumo averages
This paper investigates generalized thermodynamic relationships in physical
systems where relevant macroscopic variables are determined by the exponential
Kolmogorov-Nagumo average. We show that while the thermodynamic entropy of such
systems is naturally described by R\'{e}nyi's entropy with parameter ,
their statistics under equilibrium thermodynamics are still described by an
ordinary Boltzmann distribution, which can be interpreted as a system with
inverse temperature quenched to another heat bath with inverse
temperature . For the non-equilibrium case, we show
how the dynamics of systems described by exponential Kolmogorov-Nagumo averages
still observe a second law of thermodynamics and H-theorem. We further discuss
the applications of stochastic thermodynamics in those systems - namely, the
validity of fluctuation theorems - and the connection with thermodynamic
length.Comment: 12 pages, 1 table. arXiv admin note: text overlap with
arXiv:2203.1367
Using information theory to measure the emergence of artificial free will in a spiking brain-constrained model of the human cortex
Cell Assembly (CA) circuits are known to emerge in neurocomputational models as a result of Hebbian-like learning. Intriguingly, when a brain-like architecture is used, CAs spontaneously "ignite" in absence of any stimulus, and the patterns of network activation occurring during such ignitions closely match those observed in the human brain during non-stimulus driven, endogenous decisions to act [1]. This suggests that sub-threshold reverberation of noise within CA circuits (which drives their ignition) may be a possible mechanism underlying seemingly "free" and volitional (yet possibly pre-consciously determined) action decisions [2]. It is unclear, however, whether such spontaneous CA ignitions are truly an emergent property of the brain-like model, or whether they are somehow "pre-encoded" in the system's features. Can we provide objective evidence supporting (or falsifying) the hypothesis that these spontaneous events are de facto non pre-determined and can be thus be considered as the network's own endogenous "action decisions"?
To investigate this issue, we used a spiking brain-constrained model of six cortical areas and, after replicating the previously documented CA emergence and spontaneous ignitions in it, we analysed its emergent properties using information theoretic measures. Recent techniques in information theory allow quantifying emergence in complex systems (including the brain) [3]. Here, we applied these measures to test for the presence of emergence during spontaneous, unprovoked CA circuit ignition. Specifically, we analysed the different modalities of emergence associated with cell assembly ignition and lifecycle (downward causation and causal decoupling).
Preliminary results show the highest levels of emergent behaviour (specifically, causal decoupling) during cell assembly ignition, which gradually fade as CA activation dissipates. Such increased levels of causal decoupling observed during (and prior to) CA ignition episodes confirm the presence of an emergent feature in the neural model.
In summary, we present here the application of formal criteria used for determining the presence of emergence in complex systems to a spiking, brain-constrained neurocomputational model of the cortex that can mechanistically explain the neural origins of so-called "free", volitional action decisions. Initial results of the information-theoretical analysis indicate that spontaneous CA circuit ignitions, driven by reverberation of noise within them, truly constitute an emergent feature of the brain-like architecture, suggesting that this phenomenon should be considered as an endogenous (i.e., internally generated, and not pre-determined) feature of the artificial neural network.
References:
[1] Garagnani, M. & Pulvermüller, F. (2013) Neuronal correlates of decisions to speak and act: spontaneous emergence and dynamic topographies in a computational model of frontal and temporal areas. Brain and Language 127(1):75–85.
[2] Schurger A, Mylopoulos M, Rosenthal D. (2016) Neural antecedents of spontaneous voluntary movement: a new perspective. Trends in Cognitive Sciences. 20(2), 77-79.
[3] Rosas F.E., Mediano P.A.M., Jensen H.J., Seth A.K., Barrett A.B., Carhart-Harris R.L., et al. (2020) Reconciling emergences: An informationtheoretic approach to identify causal emergence in multivariate data. PLoS Comput Biol 16(12): e1008289
Dynamical noise can enhance high-order statistical structure in complex systems
Recent research has provided a wealth of evidence highlighting the pivotal
role of high-order interdependencies in supporting the information-processing
capabilities of distributed complex systems. These findings may suggest that
high-order interdependencies constitute a powerful resource that is, however,
challenging to harness and can be readily disrupted. In this paper we contest
this perspective by demonstrating that high-order interdependencies can not
only exhibit robustness to stochastic perturbations, but can in fact be
enhanced by them. Using elementary cellular automata as a general testbed, our
results unveil the capacity of dynamical noise to enhance the statistical
regularities between agents and, intriguingly, even alter the prevailing
character of their interdependencies. Furthermore, our results show that these
effects are related to the high-order structure of the local rules, which
affect the system's susceptibility to noise and characteristic times-scales.
These results deepen our understanding of how high-order interdependencies may
spontaneously emerge within distributed systems interacting with stochastic
environments, thus providing an initial step towards elucidating their origin
and function in complex systems like the human brain.Comment: 8 pages, 4 figures, 2 table
Pattern breaking: a complex systems approach to psychedelic medicine
Recent research has demonstrated the potential of psychedelic therapy for mental health care. However, the psychological experience underlying its therapeutic effects remains poorly understood. This paper proposes a framework that suggests psychedelics act as destabilizers, both psychologically and neurophysiologically. Drawing on the ‘entropic brain’ hypothesis and the ‘RElaxed Beliefs Under pSychedelics’ model, this paper focuses on the richness of psychological experience. Through a complex systems theory perspective, we suggest that psychedelics destabilize fixed points or attractors, breaking reinforced patterns of thinking and behaving. Our approach explains how psychedelic-induced increases in brain entropy destabilize neurophysiological set points and lead to new conceptualizations of psychedelic psychotherapy. These insights have important implications for risk mitigation and treatment optimization in psychedelic medicine, both during the peak psychedelic experience and during the subacute period of potential recovery.Peer Reviewe
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