Postural reflexes are essential for locomotion and postural stability, and may play an important role in the etiology of chronic back pain. It has recently been theoretically predicted, and with the help of unilateral perturbations of the trunk experimentally confirmed that the sensorimotor control must lower the reflex amplitude for increasing reflex delays to maintain spinal stability. The underlying neuromuscular mechanism for the compensation of postural perturbations, however, is not yet fully understood. In this study, we applied (...) unilateral and bilateral sudden external perturbations to the trunk of healthy subjects and measured the muscular activity and the movement onset of the trunk. We found that the onset of the trunk muscle activity is prior to, or coincident with, the onset of the trunk movement. Additionally, the results of our experiments imply that the muscular response mechanism integrates distant sensory information from both sides of the body. These findings rule out a simple monosynaptic stretch reflex in favor of a more complex polysynaptic postural reflex mechanism to compensate postural perturbations. Moreover, the previously predicted negative correlation between reflex delay and reflex gain was also confirmed for bilateral perturbations. (shrink)

Prolonged trunk flexion is known to affect passive and active stabilization of the trunk. Previous studies have evaluated changes in spinal range of motion, muscle activity and reflex behavior induced by prolonged trunk flexion, whereas the effect on sitting postural control is vastly underexplored. In this study, we compared the effects of supported and unsupported intermittent trunk flexion on center of pressure motion during sitting on an unstable seat. Participants were exposed to 1-h intermittent trunk flexion and CoP root (...) mean square distance, velocity and frequency before and after the exposure were assessed. Contrary to our hypothesis, there were no main effects of exposure, no main effects of condition, and no interaction between exposure and condition. Our results indicate that prolonged intermittent flexion does not induce any changes in CoP motion during a seated balance task, regardless of the presence of a trunk support during prolonged intermittent flexion. This suggests a successful compensation of decreased passive stiffness by increased reflex activity. (shrink)

Trinucleotide repeat expansions are now a well‐established mutational mechanism in human genetic disease. An unstable CAG repeat is known to be responsible for three neurodegenerative disorders: Huntington's disease, spinal and bulbar musclar atrophy and spinocerebellar ataxia type 1. Similarities in the genetics of these diseases, the size of the repeat expansions and the position of the unstable repeat within the gene (when known) suggest a common basis to the observed phenotypes. The cloning of two regions at which chromosome breakage (...) can be induced (FRAXA and FRAXE) has in each case uncovered an unstable CG‐rich triplet repeat which becomes methylated when fully expanded. In addition to these two classes of mutation, the presence of an expanded CTG repeat in the 3′ untranslated region of a protein kinase causes myotonic dystrophy. The size of the respective expansions, repeat stability, mutational origins and possible mechanisms of action are discussed. (shrink)

The historical continuity of spinal catastrophism, traced across multiform encounters between philosophy, psychology, biology, and geology. Drawing on cryptic intimations in the work of J. G. Ballard, Georges Bataille, William Burroughs, Andre Leroi-Gourhan, Elaine Morgan, and Friedrich Nietzsche, in the late twentieth century Daniel Barker formulated the axioms of spinal catastrophism: If human morphology, upright posture, and the possibility of language are the ramified accidents of natural history, then psychic ailments are ultimately afflictions of the spine, which itself (...) is a scale model of biogenetic trauma, a portable map of the catastrophic events that shaped that atrocity exhibition of evolutionary traumata, the sick orthograde talking mammal. Tracing its provenance through the biological notions of phylogeny and "organic memory" that fueled early psychoanalysis, back into idealism, nature philosophy, and romanticism, and across multiform encounters between philosophy, psychology, biology, and geology, Thomas Moynihan reveals the historical continuity of spinal catastrophism. From psychoanalysis and myth to geology and neuroanatomy, from bioanalysis to chronopathy, from spinal colonies of proto-minds to the retroparasitism of the CNS, from "railway spine" to Elizabeth Taylor's lost gill-slits, this extravagantly comprehensive philosophical adventure uses the spinal cord as a guiding thread to rediscover forgotten pathways in modern thought. Moynihan demonstrates that, far from being an fanciful notion rendered obsolete by advances in biology, spinal catastrophism dramatizes fundamental philosophical problematics of time, identity, continuity, and the transcendental that remain central to any attempt to reconcile human experience with natural history. (shrink)

The spinal cord provides an alternative model for nerve tissue grafting experiments. Anatomo-functional correlations are easier to make here than in any other region of the CNS because of a direct implication of spinal cord neurons in sensorimotor activities. Lesions can be easily performed to isolate spinal cord neurons from descending inputs. The anatomy of descending monoaminergic systems is well defined and these systems offer a favourable paradigm for lesion-graft experiments.

The hereditary neurodegenerative disease spinal muscular atrophy (SMA) with childhood onset is one of the most common genetic causes of infant mortality. The disease is characterized by selective loss of spinal cord motor neurons leading to muscle atrophy and is the result of mutations in the survival motor neuron (SMN) gene. The SMN protein has been implicated in diverse nuclear processes including splicing, ribosome formation and gene transcription. Even though the genetic basis of SMA is well understood, it (...) is not clear how defects in these ubiquitous processes result in motor neuron degeneration leaving other tissues unaffected. Recent evidence from animal and cell culture models of SMA points to roles for SMN in neurite outgrowth and axonal transport. Disruption of these functions might be particularly detrimental to motor neurons given their high metabolic demands and precise connectivity requirements, thus providing a possible explanation for the specificity of motor neuron susceptibility in SMA. Understanding the molecular mechanisms of SMN activity in neuronal processes may generate new targets for future therapeutic strategies. BioEssays 27:946–957, 2005. © 2005 Wiley Periodicals, Inc. (shrink)

As infancy is characterized by rapid physical growth and critical periods of development, disruptions due to illness or disease reveal vulnerability associated with this period. Spinal cord injury has devastating consequences at any age, but its onset neonatally, at birth, or within the first year of life multiplies its impact. The immediate physical and physiological consequences are obvious and immense, but the effects on the typical trajectory of development are profound. Activity-based restorative therapies capitalize on activity-dependent plasticity of the (...) neuromuscular system below the lesion and when provided to children with SCI aim to improve the child’s neuromuscular capacity, health and quality of life. This is a report of an infant with a cervical SCI at birth resulting in paralysis of leg and trunk muscles and paresis of arm and hands who was enrolled in an ABRT program at 3 years of age. After 59 sessions of ABRT, the child demonstrated significant improvements in trunk control and arm function, as well as social and emotional development. Despite the chronicity of injury and low expectations for improvement with therapeutic interventions, ABRT had a positive impact on the child’s physical capacity and provided benefits across multiple developmental domains. (shrink)

Seen as contributing to human enhancement, implanted technologies have recently been receiving a lot of attention. However, reflections on these technologies have taken the shape of rather speculative ethical judgments on “hyped” technological devices. On the other hand, while science and technology studies and philosophy of technology have a long tradition of analyzing how technological artifacts and tools transform and configure our lives, they tend to focus on use configurations rather than the intimate relations brought about by implanted technologies. Even (...) the cyborg has lost some of its hermeneutic power as it has been detached from its material grounds, becoming a discursive entity. In this article, I reclaim the importance of materiality and explore how people live with spinal cord stimulation, which is a type of neuromodulation technology. Implanted in bodies and seemingly out of sight, this technology does not cease to matter. Embodiment and incorporation are crucial for people to live well with SCS. Embodying the neuromodulation technology entails groping processes in which gestures are central and an increased intimacy with one’s bodily materiality. Incorporating it is highly relational and entangled with the bodies of loved and distant ones, humans and nonhumans. (shrink)

Electroencephalographic correlates of movement have been studied extensively over many years. In the present work, we focus on investigating neural correlates that originate from the spine and study their connectivity to corresponding signals from the sensorimotor cortex using multivariate autoregressive models. To study cortico-spinal interactions, we simultaneously measured spinal cord potentials and somatosensory evoked potentials of wrist movements elicited by neuromuscular electrical stimulation. We identified directional connections between spine and cortex during both the extension and flexion of the (...) wrist using only non-invasive recording techniques. Our connectivity estimation results are in alignment with various studies investigating correlates of movement, i.e., we found the contralateral side of the sensorimotor cortex to be the main sink of information as well as the spine to be the main source of it. Both types of movement could also be clearly identified in the time-domain signals. (shrink)

We introduce LTAG-spinal, a novel variant of traditional Lexicalized Tree Adjoining Grammar (LTAG) with desirable linguistic, computational and statistical properties. Unlike in traditional LTAG, subcategorization frames and the argument-adjunct distinction are left underspecified in LTAG-spinal. LTAG-spinal with adjunction constraints is weakly equivalent to LTAG. The LTAG-spinal formalism is used to extract an LTAG-spinal Treebank from the Penn Treebank with Propbank annotation. Based on Propbank annotation, predicate coordination and LTAG adjunction structures are successfully extracted. The LTAG- (...) class='Hi'>spinal Treebank makes explicit semantic relations that are implicit or absent from the original PTB. LTAG-spinal provides a very desirable resource for statistical LTAG parsing, incremental parsing, dependency parsing, and semantic parsing. This treebank has been successfully used to train an incremental LTAG-spinal parser and a bidirectional LTAG dependency parser. (shrink)

In 1923, Sir Arthur Keith proposed that many common back problems are due to the stresses caused by our evolutionarily novel form of locomotion, bipedalism. In this article, we introduce an updated version of Keith’s hypothesis with a focus on acquired spinal conditions. We begin by outlining the main ways in which the human spine differs from those of our closest living relatives, the great apes. We then review evidence suggesting there is a link between spinal and vertebral (...) shape on the one hand and acquired spinal conditions on the other. Next, we discuss recent studies that not only indicate that two common acquired spinal conditions—intervertebral disc herniation and spondylolysis—are associated with vertebral shape, but also suggest that the pathology-prone vertebral shapes can be understood in terms of the shift from quadrupedalism to bipedalism in the course of human evolution. Subsequently, we place the aforementioned findings under an umbrella hypothesis, which we call the “Evolutionary Shape Hypothesis.” This hypothesis contends that individuals differ in their propensity to develop different acquired spinal conditions because of differences in vertebral shape that relate to the evolutionary history of our species. We end the article with some possible directions for future research. (shrink)

It is argued that the Nash bargaining solution cannot serve as a principle of distributive justice because (i) it cannot secure stable cooperation in repeated interactions and (ii) it cannot capture our moral intuitions concerning distributive questions. In this article, I propose a solution to the first problem by amending the Nash bargaining solution so that it can maintain stable cooperation among rational bargainers. I call the resulting principle the stabilized Nash bargaining solution. The principle defends justice in the form (...) 'each according to her basic needs and above this level according to her relative bargaining power'. In response to the second problem, I argue that the stabilized Nash bargaining solution can serve as a principle of distributive justice in certain situations where moral reasoning is reduced to instrumental reasoning. In particular, I argue that rational individuals would choose the stabilized Nash bargaining solution in Rawls' original position. (shrink)

In this article, I argue that stability is one of the enabling conditions for epistocratic arrangements to function well and justify their claim right to rule. Against this backdrop, I demonstrate that advocates of strategies to allocate exclusive decision-making power to knowledgeable citizens fail to demonstrate that in a context marked by the fact of pluralism, liberal epistocracies will be stable. They could argue that liberal epistocracies will be stable because epistocratic arrangements are better equipped than democratic decision-making bodies (...) to produce outcomes that approximate the common good. They could argue that liberal epistocracies will be stable because there is a shared meritocratic set of values and ideas. Furthermore, they could opt for two standard liberal strategies, such as overlapping consensus and modus vivendi. Yet, in all cases, the argument for the stability of liberal epistocracies is not persuasive. (shrink)

Much recent work on explanation in the interventionist tradition emphasizes the explanatory value of stable causal generalizations—i.e., causal generalizations that remain true in a wide range of background circumstances. We argue that two separate explanatory virtues are lumped together under the heading of `stability’. We call these two virtues breadth and guidance respectively. In our view, these two virtues are importantly distinct, but this fact is neglected or at least under-appreciated in the literature on stability. We argue that (...) an adequate theory of explanatory goodness should recognize breadth and guidance as distinct virtues, as breadth and guidance track different ideals of explanation, satisfy different cognitive and pragmatic ends, and play different theoretical roles in helping us understand the explanatory value of mechanisms. Thus keeping track of the distinction between these two forms of stability yields a more accurate and perspicuous picture of the role that stability considerations play in explanation. (shrink)

In everyday life we either express our beliefs in all-or-nothing terms or we resort to numerical probabilities: I believe it's going to rain or my chance of winning is one in a million. The Stability of Belief develops a theory of rational belief that allows us to reason with all-or-nothing belief and numerical belief simultaneously.

The distinguished philosopher Louis Loeb examines the epistemological framework of Scottish philosopher David Hume, as employed in his celebrated work A Treatise of Human Nature. Loeb's project is to advance an integrated interpretation of Hume's accounts of belief and justification. His thesis is that Hume, in his Treatise, has a "stability-based" theory of justification which posits that his belief is justified if it is the result of a belief producing mechanism that engenders stable beliefs. But Loeb argues that the (...) striking corollary to this theory is that no belief generating mechanism is fully stable - or fully justified - for a fully reflective person. This carefully argued and original interpretation of Hume makes sense of seemingly contradictory ideas and will provoke serious discussion among Hume scholars. (shrink)

I investigate the role of stability in cosmology through two episodes from the recent history of cosmology: Einstein’s static universe and Eddington’s demonstration of its instability, and the flatness problem of the hot big bang model and its claimed solution by inflationary theory. These episodes illustrate differing reactions to instability in cosmological models, both positive ones and negative ones. To provide some context to these reactions, I also situate them in relation to perspectives on stability from dynamical systems (...) theory and its epistemology. This reveals, for example, an insistence on stability as an extreme position in relation to the spectrum of physical systems which exhibit degrees of stability and fragility, one which has a pragmatic rationale, but not any deeper one. (shrink)

Despite great advances in recent scholarship on the political philosophy of John Rawls, Rawls’s conception of stability is not fully appreciated. This essay aims to remedy this by articulating a more complete understanding of stability and its role in Rawls’s theory of justice. I argue that even in A Theory of Justice Rawls maintains that within liberal democratic constitutionalism judgments of relative stability typically adjudicate decisively among conceptions of justice and is committed to more deeply than to (...) the substantive content of justice as fairness. This essay thus emphasizes the continuity of Rawls’s thought over time and motivates the position that Rawlsian stability is as philosophically significant and distinctively Rawlsian as justice as fairness itself. (shrink)

Grossberg and VanDieren have started a program to develop a stability theory for tame classes. We name some variants of tameness and prove the following. Let K be an AEC with Löwenheim-Skolem number ≤κ. Assume that K satisfies the amalgamation property and is κ-weakly tame and Galois-stable in κ. Then K is Galois-stable in κ⁺ⁿ for all n<ω. With one further hypothesis we get a very strong conclusion in the countable case. Let K be an AEC satisfying the amalgamation (...) property and with Löwenheim-Skolem number ℵ₀ that is ω-local and ℵ₀-tame. If K is ℵ₀-Galois-stable then K is Galois-stable in all cardinalities. (shrink)

We address the question whether there is an explanation for the fact that as Fodor put it the micro-level “converges on stable macro-level properties”, and whether there are lessons from this explanation for other issues in the vicinity. We argue that stability in large systems can be understood in terms of statistical limit theorems. In the thermodynamic limit of infinite system size N → ∞ systems will have strictly stable macroscopic properties in the sense that transitions between different macroscopic (...) phases of matter (if there are any) will not occur in finite time. Indeed stability in this sense is a consequence of the absence of fluctuations, as (large) fluctuations would be required to induce such macroscopic transformations. These properties can be understood in terms of coarse-grained descriptions, and the statistical limit theorems for independent or weakly dependent random variable describing the behaviour averages and the statistics of fluctuations in the large system limit. We argue that RNG analyses applied to off-critical systems can provide a rationalization for the applicability of these limit theorems. Furthermore we discuss some related issues as, for example, the role of the infinite-system idealization. (shrink)

An attractive form of social stability is realized when the members of a well-ordered society give that society’s organizing principles their free and reflective endorsement. However, many political philosophers are skeptical that there is any requirement to show that their principles would engender this kind of stability. This skepticism is at the root of a number of objections to political liberalism, since arguments for political liberalism often appeal to its ability to be stable in this way. The aim (...) of this paper is to address skepticism about the stability condition by putting forward a novel defense of it. My defense builds on the claim that stable principles are necessary to secure the full autonomy of those who live under them. (shrink)

Several authors have investigated the question of whether canonical logic-based accounts of belief revision, and especially the theory of AGM revision operators, are compatible with the dynamics of Bayesian conditioning. Here we show that Leitgeb's stability rule for acceptance, which has been offered as a possible solution to the Lottery paradox, allows to bridge AGM revision and Bayesian update: using the stability rule, we prove that AGM revision operators emerge from Bayesian conditioning by an application of the principle (...) of maximum entropy. In situations of information loss, or whenever the agent relies on a qualitative description of her information state - such as a plausibility ranking over hypotheses, or a belief set - the dynamics of AGM belief revision are compatible with Bayesian conditioning; indeed, through the maximum entropy principle, conditioning naturally generated AGM revision operators. This mitigates an impossibility theorem of Lin and Kelly for tracking Bayesian conditioning with AGM revision, and suggests an approach to the compatibility problem that highlights the information loss incurred by acceptance rules in passing from probabilistic to qualitative representations of beliefs. (shrink)

In this working paper, we discuss why researchers and policymakers need to better understand how different theoretical accounts of stability lead to different frameworks of analysis. Though ubiquitously mentioned, stability remains an under-theorized notion in security studies. Expert accounts tend to present stability as a generic description, readily applicable to most political phenomena Ð a stabilized state, a stable region, an unstable society. While seemingly equivocal, such uses exhibit different conceptualizations, exhibiting different features and demanding multiple research (...) programs. To date, most accounts of stability tend to take stability to be an (unconstructed) natural phenomenon or a non-derivative social construction. In this introductory paper, we claim that there is a third way to account for stability that remains unexplored in security studies. Simply put, it involves taking stability to be a derivative social construction (i.e., systemic fallout). We then argue that this alternative account should serve as the theoretical basis for an independent research program within stability studies. (shrink)

In this paper I discuss the relation between various properties that have been regarded as important for determining whether or not a belief constitutes a piece of knowledge: its stability, strength and sensitivity to truth, as well as the strength of the epistemic position in which the subject is with respect to this belief. Attempts to explicate the relevant concepts more formally with the help of systems of spheres of possible worlds (à la Lewis and Grove) must take care (...) to keep apart the very different roles that systems of spheres can play. Nozicks sensitivity account turns out to be closer to the stability analysis of knowledge (versions of which I identify in Plato, Descartes, Klein and Lehrer) than one might have suspected. (shrink)

Bourrat and Griffiths :33, 2018) have recently argued that most of the evidence presented by holobiont defenders to support the thesis that holobionts are evolutionary individuals is not to the point and is not even adequate to discriminate multispecies evolutionary individuals from other multispecies assemblages that would not be considered evolutionary individuals by most holobiont defenders. They further argue that an adequate criterion to distinguish the two categories is fitness alignment, presenting the notion of fitness boundedness as a criterion that (...) allows divorcing true multispecies evolutionary individuals from other multispecies assemblages and provides an adequate criterion to single out genuine evolutionary multispecies assemblages. A consequence of their criterion is that holobionts, as conventionally defined by hologenome defenders, are not evolutionary individuals except in very rare cases, and for very specific host-symbiont associations. This paper is a critical response to Bourrat and Griffiths’ arguments and a defence of the arguments presented by holobiont defenders. Drawing upon the case of the hologenomic basis of the evolution of sanguivory in vampire bats, I argue that Bourrat and Griffiths overlook some aspects of the biological nature of the microbiome that justifies the thesis that holobionts are evolutionarily different to other multispecies assemblages. I argue that the hologenome theory of evolution should not define the hologenome as a collection of genomes, but as the sum of the host genome plus some traits of the microbiome which together constitute an evolutionary individual, a conception I refer to as the stability of traits conception of the hologenome. Based on that conception I argue that the evidence presented by holobiont defenders is to the point, and supports the thesis that holobionts are evolutionary individuals. In this sense, the paper offers an account of the holobiont that aims to foster a dialogue between hologenome advocates and hologenome critics. (shrink)

Spinal muscular atrophy (SMA) type 1 is a genetic neuromuscular disease in children that leads to degeneration of spinal cord motor neurons. This sometimes results in severe muscular paralysis requiring mechanical ventilation to sustain the child’s life. The onset of SMA type 1, the most severe form of the disease, is during the first year of life. These children become severely paralysed, but retain their intellectual capacity. Ethical concerns arise when mechanical ventilation becomes necessary for survival. When professionals (...) assess the resulting life for the child and family, they sometimes fear it will result in unreasonably excessive care. The aim of this article is to present an analysis of ethical arguments that could support or oppose the provision of invasive ventilation in this population. This examination is particularly relevant as France is one of the few countries performing tracheotomies and mechanical ventilation for this condition. (shrink)