Metastability Research Papers - Academia.edu (original) (raw)

The topic of this Oxford handbook is “4E cognition”: cognition as embodied, embedded, enactive, and extended. However, one important “E” is missing: an E for ecological. We sketch an ecological-enactive approach to cognition that presents... more

The topic of this Oxford handbook is “4E cognition”: cognition as embodied, embedded, enactive, and extended. However, one important “E” is missing: an E for ecological. We sketch an ecological-enactive approach to cognition that presents a framework for bringing together the embodied/enactive program with the ecological program originally developed by James Gibson, in which affordances are central. We call this framework the skilled intentionality framework. The skilled intentionality framework is a philosophical approach to understanding the situated and affective embodied mind. It is a new conceptual framework for the field of 4E cognitive science that focuses on skilled action and builds upon an enriched notion of affordances. We define skilled intentionality as the selective engagement with multiple affordances simultaneously in a concrete situation. The skilled intentionality framework clarifies how complementary insights on affordance responsiveness from philosophy/phenomenology, ecological psychology, emotion psychology, and neurodynamics hang together in an intertwined way.

In this article, we investigate the foundations for a Gibsonian neurosci- ence. There is an increasingly influential current in neuroscience based on pragmatic and selectionist principles, which we think can contrib- ute to ecological... more

In this article, we investigate the foundations for a Gibsonian neurosci-
ence. There is an increasingly influential current in neuroscience based
on pragmatic and selectionist principles, which we think can contrib-
ute to ecological psychology. Starting from ecological psychology, we
identify three basic constraints any Gibsonian neuroscience needs to
adhere to: nonreconstructive perception, vicarious functioning, and
selectionist self-organization. We discuss two previous attempts to
integrate affordances with neuroscience: Reed’s ecological rendering of Edelman’s selectionism as well as Dreyfus’ phenomenological inter- pretation of Freeman’s neurodynamics. Reed and Dreyfus face the problem of how to account for “value.”
We then show how the free-energy principle, an increasingly dominant framework in theoretical neuroscience, is rooted in both Freeman’s neurodynamics and Edelman’s selectionism. The free-energy principle accounts for value in terms of selective anticipation. The selection pressures at work on the agent shape its selective sensitivity to the relevant affordances in the environment. By being responsive to the relevant affordances in the environment, an agent comes to have grip on its interactions
with the environment and can thrive in its ecological niche.

This commentary focuses on a complementary theoretical– experimental approach to the target article by Hill, Den Hartigh, Meijer, De Jonge, and Van Yperen (2018). In the target article, the authors develop an initial roadmap for... more

This commentary focuses on a complementary theoretical– experimental approach to the target article by Hill, Den Hartigh, Meijer, De Jonge, and Van Yperen (2018). In the target article, the authors develop an initial roadmap for identifying persistent behavioral patterns (i.e., athletic resilience) through measurements to identify specific attractor states and/or the attractor landscape. The goal of this approach is to promote a more complete understanding of the underlying attractor dynamics that give rise to resilient behavior. We extend the thesis of the target article via the concept of metastability. Metastable dynamics are the result of the system remaining poised on the edge of criticality. We argue that metastability is key for positively adapted behavior and, ultimately, successful athletic performance. When considered in this light, positive adaptations to adversity (i.e., resilience) are the minimum outcome, with performance enhancement in the face of adversity as the true performance goal. Such growth from adversity is termed antifragility. We next couch this concept in the context of evolutionary biology to leverage biological hormesis as a stress-response model for athletic performance. This allows for biology-inspired fitness profiles that provide a quantifiable measure of stress response relative to environmental change. From there, phenotypic plasticity can be calculated to further elucidate the relation between adversity and performance responses as a quantifiable index of antifragility. Finally, this approach is discussed in the context of personalized training interventions that facilitate the emergence of metastable dynamics that underlie phenotypic plasticity, with critical training windows introduced as opportunities to increase athletic antifragility.

In everyday situations, and particularly in some sport and working contexts, humans face an inherently unpredictable and uncertain environment. All sorts of unpredictable and unexpected things happen but typically people are able to... more

In everyday situations, and particularly in some sport and working contexts, humans
face an inherently unpredictable and uncertain environment. All sorts of unpredictable
and unexpected things happen but typically people are able to skillfully adapt. In
this paper, we address two key questions in cognitive science. First, how is an agent
able to bring its previously learned skill to bear on a novel situation? Second, how
can an agent be both sensitive to the particularity of a given situation, while remaining
flexibly poised for many other possibilities for action? We will argue that both
the sensitivity to novel situations and the sensitivity to a multiplicity of action possibilities
are enabled by the property of skilled agency that we will call metastable
attunement. We characterize a skilled agent’s flexible interactions with a dynamically
changing environment in terms of metastable dynamics in agent-environment
systems. What we find in metastability is the realization of two competing tendencies:
the tendency of the agent to express their intrinsic dynamics and the tendency
to search for new possibilities. Metastably attuned agents are ready to engage with a
multiplicity of affordances, allowing for a balance between stability and flexibility.
On the one hand, agents are able to exploit affordances they are attuned to, while
at the same time being ready to flexibly explore for other affordances. Metastable
attunement allows agents to smoothly transition between these possible configurations
so as to adapt their behaviour to what the particular situation requires. We go
on to describe the role metastability plays in learning of new skills, and in skilful
behaviour more generally. Finally, drawing upon work in art, architecture and sports
science, we develop a number of perspectives on how to investigate metastable
attunement in real life situations.

Background: The functional architecture of resting-state networks (RSNs) is defined by their connectivity and metastability. Disrupted RSN connectivity has been amply demonstrated in schizophrenia while the role of meta-stability remains... more

Background: The functional architecture of resting-state networks (RSNs) is defined by their connectivity and metastability. Disrupted RSN connectivity has been amply demonstrated in schizophrenia while the role of meta-stability remains poorly defined. Here, we undertake a comprehensive characterisation of RSN organization in schizophrenia and test its contribution to the clinical profile of this disorder. Methods: We extracted RSNs representing the default mode (DMN), central executive (CEN), salience (SAL), language (LAN), sensorimotor (SMN), auditory (AN) and visual (VN) networks from resting-state functional magnetic resonance imaging data obtained from patients with schizophrenia (n = 85) and healthy individuals (n = 48). For each network, we computed its functional cohesiveness and integration and used the Kuramoto order parameter to compute metastability. We used stepwise multiple regression analyses to test these RSN features as predictors of symptom severity in patients. Results: RSN features respectively explained 14%, 17%, 12% and 5% of the variance in positive, negative, anxious/ depressive and agitation/disorganization symptoms. Lower functional integration between the DMN, CEN and SMN primarily contributed to positive symptoms. The functional properties of the SAL network were key predic-tors of all other symptom dimensions; specifically, lower cohesiveness of the SAL, lower integration of this network with the LAN and higher integration with the CEN respectively contributed to negative, anxious/depressive and disorganization symptoms. Increased SAL metastability was associated with negative symptoms. Conclusions: These results confirm the primacy of the SAL network for schizophrenia and demonstrate that abnormalities in RSN connectivity and metastability are significant predictors of schizophrenia-related psychopathology.

A series of nanocrystalline Fe–C alloys with different carbon concentrations (xtot) up to 19.4 at.% (4.90 wt.%) are prepared by ball milling. The microstructures of these alloys are characterized by transmission electron microscopy and... more

A series of nanocrystalline Fe–C alloys with different carbon concentrations (xtot) up to 19.4 at.% (4.90 wt.%) are prepared by ball milling. The microstructures of these alloys are characterized by transmission electron microscopy and X-ray diffraction, and partitioning of carbon between grain boundaries and grain interiors is determined by atom probe tomography. It is found that the segregation of carbon to grain boundaries of a-ferrite can significantly reduce its grain size to a few nanometers. When the grain boundaries of ferrite are saturated with carbon, a metastable thermodynamic equilibrium between the matrix and the grain boundaries is approached, inducing a decreasing grain size with increasing xtot. Eventually the size reaches a lower limit of about 6 nm in alloys with xtot > 6.19 at.% (1.40 wt.%); a further increase in xtot leads to the precipitation of carbon as Fe3C. The observed presence of an amorphous structure in 19.4 at.% C (4.90 wt.%) alloy is ascribed to a deformation-driven amorphization of Fe3C by severe plastic deformation. By measuring the temperature dependence of the grain size for an alloy with 1.77 at.% C additional evidence is provided for a metastable equilibrium reached in the nanocrystalline alloy.

Metastability is currently considered a fundamental property of the functional configuration of brain networks. The present study sought to generate a normative reference framework for the metastability of the major resting-state networks... more

Metastability is currently considered a fundamental property of the functional configuration of brain networks. The present study sought to generate a normative reference framework for the metastability of the major resting-state networks (RSNs) (resting-state metastability dataset) and discover their association with demographic, behavioral, physical and cognitive features (non-imaging dataset) from 818 participants of the Human Connectome Project. Using sparse canonical correlation analysis, we found that the metastability and non-imaging datasets showed significant but modest interdependency. Notable associations between the metastability variate and the non-imaging features were observed for higher-order cognitive ability and indicators of physical well-being. The intra-class correlation coefficient between the sibling pairs in the sample was very low which argues against a significant familial influence on RSN metastability.

In this paper, we use circuit simulations to characterize the effects of technology scaling on the metastability parameters of CMOS latches used as synchronizers. We perform this characterization by obtaining a synchronization error... more

In this paper, we use circuit simulations to characterize the effects of technology scaling on the metastability parameters of CMOS latches used as synchronizers. We perform this characterization by obtaining a synchronization error probability curve from a histogram of the latch delay. The main metastability parameters of CMOS latches are τm and Tw. τm is the exponential time constant of the rate of decay of metastability and T w is effective metastability window size at a normal propagation delay. Both parameters can be extracted from a histogram of the latch delay. This paper also explains a way to calibrate the simulator for accuracy. The simulations indicate that τm scales better than the technology scale factor. Tw also scales down but its factor cannot be estimated as well as that of τ m. This is because Tw is a complex function of signal and clock edge rate and logic threshold level

Rapid advances in the field of neuroimaging techniques including magnetoencephalography (MEG), electroencephalography (EEG), functional MRI (fMRI), diffusion tensor imaging (DTI), voxel based morphomentry (VBM), and optical imaging, have... more

Rapid advances in the field of neuroimaging techniques including magnetoencephalography (MEG), electroencephalography (EEG), functional MRI (fMRI), diffusion tensor imaging (DTI), voxel based morphomentry (VBM), and optical imaging, have allowed neuroscientists to investigate neural processes in ways that have not been possible until recently. Combining these techniques with advanced analysis procedures during different conditions such as hypnosis, psychiatric and neurological conditions, subliminal stimulation, and psychotropic drugs began transforming the study of neuroscience, ushering a new paradigm that may allow neuroscientists to tackle the hard problem of consciousness.

Despite allowing for the unprecedented visualization of brain functional activity, modern neurobiological techniques have not yet been able to provide satisfactory answers to important questions about the relationship between brain and... more

Despite allowing for the unprecedented visualization of brain functional activity, modern neurobiological techniques have not yet been able to provide satisfactory answers to important questions about the relationship between brain and mind. The aim of this paper is to show how two different but complementary approaches, Mind Operational Semantics (OS) and Brain Operational Architectonics (OA), can help bridge the gap between a specific kind of mental activity-the higher-order reflective thought or linguistic thought-and brain. The fundamental notion that allows the two different approaches to be jointly used under a common framework is that of operation. According to OS, which is based on introspection and linguistic data, the meanings of words can be analyzed in terms of elemental mental operations (EOMC), amongst which those of attention play a key role. Linguistic thought is made possible by special kinds of elements, which OS calls "correlators", which have the functi...

The functional architecture of resting-state networks (RSNs) is defined by their connectivity and metastability. Disrupted RSN connectivity has been amply demonstrated in schizophrenia while the role of metastability remains poorly... more

The functional architecture of resting-state networks (RSNs) is defined by their connectivity and metastability. Disrupted RSN connectivity has been amply demonstrated in schizophrenia while the role of metastability remains poorly defined. Here, we undertake a comprehensive characterisation of RSN organization in schizophrenia and test its contribution to the clinical profile of this disorder. We extracted RSNs representing the default mode (DMN), central executive (CEN), salience (SAL), language (LAN), sensorimotor (SMN), auditory (AN) and visual (VN) networks from resting-state functional magnetic resonance imaging data obtained from patients with schizophrenia (n = 85) and healthy individuals (n = 48). For each network, we computed its functional cohesiveness and integration and used the Kuramoto order parameter to compute metastability. We used stepwise multiple regression analyses to test these RSN features as predictors of symptom severity in patients. RSN features respective...

Amorphous silicon (a-Si:H) thin-film transistors (TFTs) used in emerging, nonswitch applications such as analog amplifiers or active loads, often have a bias at the drain terminal in addition to the gate that can alter their threshold... more

Amorphous silicon (a-Si:H) thin-film transistors (TFTs) used in emerging, nonswitch applications such as analog amplifiers or active loads, often have a bias at the drain terminal in addition to the gate that can alter their threshold voltage (VT) stability performance. At small gate stress voltages (0≤VST≤15 V) where the defect state creation instability mechanism is dominant, the presence of a

Scale free dynamics and scale invariance are universal characteristics of complex systems in nature. 1/f or long-range temporal correlations or pink noise is also a self-generated/correlated brain noise that coexists with periodic brain... more

Scale free dynamics and scale invariance are universal characteristics of complex systems in nature. 1/f or long-range temporal correlations or pink noise is also a self-generated/correlated brain noise that coexists with periodic brain oscillations in a non predominant temporal fashion. For a long time this kind of noise has been ignored in experimental manipulations or analyses because thought to be the expression of instrumental noise. Nowadays, instead, recent evidence speaks in favour of the functional significance of the 1/f and its spatiotemporal organisation at different levels. However, further investigation is needed in order to unveil the relationship between each specific 1/f noise (across individuals, behavioural tasks, across different natural phenomena…). Outline of the lecture: 1. Power-law distributions in nature 2. Types of noise 3. 1/f as a signature of complexity 4. Debate between brain oscillations and noise 5. New perspectives on 1/f: functional significance and temporal organisation.

We briefly discuss the state of the art on the anomalous dynamics of the Hamiltonian mean field (HMF) model. We stress the important role of the initial conditions for understanding the microscopic nature of the intriguing metastable... more

We briefly discuss the state of the art on the anomalous dynamics of the Hamiltonian mean field (HMF) model. We stress the important role of the initial conditions for understanding the microscopic nature of the intriguing metastable quasi-stationary states (QSS) observed in the model and the connections to Tsallis statistics and glassy dynamics. We also present new results on the existence of metastable states in the Kuramoto model and discuss the similarities with those found in the HMF model. The existence of metastability seems to be quite a common phenomenon in fully coupled systems, whose origin could be also interpreted as a dynamical mechanism preventing or hindering synchronization.