ABSTRACT According to contemporary diagnoses, democracy is foundering because of polarization. It is natural to think that if polarization is a problem, the remedy is to reconcile the conflicting sides. Yet reconciliation seems to involve the disturbing prescription that citizens should reconcile with radicals who have divested from democratic norms. That assumes, however, that polarization is symmetrical, whereby each side is equally responsible for it. But polarization need not depend on the assumption of such symmetry, such that depolarization may (...) be possible without reconciliation. If so, polarization may be a problem not only between political alliances but within them. (shrink)

Laurie Shrage attributes much of the long-standing controversy about abortion to Roe v. Wade and to the Supreme Court's controversial regulatory scheme in that 1973 decision. Shrage explores the origins of that scheme but argues for an alternate scheme - therapeutic abortions shorter than six months can protect women's interests and advance important public interests, but that reproductive rights campaigns should also focus on the social and economic conditions that prevent women having access to the abortion services they need. Including (...) over 40 illustrations of pro-life and pro-choice advertisements to demonstrate the nature of the debate, this timely and provocative work will appeal to feminists in a wide range of fields including philosophy, political science, women's studies, communication, and public policy. (shrink)

The pejorative connotation often associated with the ordinary language meaning of “conspiracy theory” does not only stem from a conspiracy theory’s being about a conspiracy, but also from a conspiracy theory’s being regarded as a particular kind of theory. I propose to understand conspiracy theory-induced polarization in terms of disagreement about the correct epistemic evaluation of ‘theory’ in ‘conspiracy theory’. By framing the positions typical in conspiracy theory-induced polarization in this way, I aim to show that pejorative conceptions of ‘conspiracy (...) theory’ are problematic for research open to the possibility of finding depolarization strategies. That is, because they preclude constructive engagement with the epistemic norms governing (the rationales foundational of) belief in conspiracy theories. (shrink)

Although we are beginning to understand the neuronal and biochemical nature of sleep regulation, questions remain about how sleep is homeostatically regulated. Beyond its importance in basic physiology, understanding sleep may also shed light on psychiatric and neurodevelopmental disorders. Recent genetic studies in mammals revealed several non-secretory proteins that determine sleep duration. Interestingly, genes identified in these studies are closely related to psychiatric and neurodevelopmental disorders, suggesting that the sleep-wake cycle shares some common mechanisms with these disorders. Here we review (...) recent sleep studies, including reverse and forward genetic studies, from the perspectives of sleep duration and homeostasis. We then introduce a recent hypothesis for mammalian sleep in which the fast and slow Ca2+-dependent hyperpolarization pathways are pivotal in generating the SWS firing pattern and regulating sleep homeostasis, respectively. Finally, we propose that these intracellular pathways are potential therapeutic targets for achieving depolarization/hyperpolarization balance in psychiatric and neurodevelopmental disorders. How animals implement sleep homeostasis is a great mystery. Here, we review recent studies with highlighting the hypothesis that the slow Ca2+-dependent hyperpolarization pathway regulates sleep homeostasis via modifying the fast pathway; the activity of CaMKIIα/β increases during wakefulness, which triggers sleep by phosphorylating the components in the fast pathway. (shrink)

Social scientists have observed a sharp rise in affective polar­ization in many societies, particularly the United States. Since it is widely agreed that this poses a threat to democracy, finding solutions to this predicament is essential. One prominent proposal to depolarize the electorate holds that citizens need to exercise their capacities for empathy with the political opposition. However, defenders of the empathy response to affective polarization have yet to fully specify the range of mechanisms through which empathy can counteract polarization. (...) Recent proposals focus on empathy’s role in finding common ground and humanizing others. Drawing on the wider empathy literature, we identify several additional ways empathy might counter affective polarization. We show that the resultant account has important implications for the sorts of empathetic engagement with cross-partisans that is likely to reduce polarization. Our aim is to contribute to a deeper understanding of the potential of different kinds of empathetic engagement to counter polarization as well as the limits of empathy as a response to polarization. (shrink)

Libet discovered that a substantial duration (> 0.5-1.0 s) of direct electrical stimulation of the surface of the somatosensory cortex at threshold currents is required before human subjects can report that a conscious somatosensory experience had occurred. Using a reaction time method we confirm that a similarly long stimulation duration at threshold currents is required for activation of elementary visual experiences (phosphenes) in human subjects following stimulation of the surface of the striate cortex. However, the reaction times for the subject (...) to respond to the cessation of the visual experience after the end of electrical stimulation could be as brief as 225-242 ms. We also carried out extensive studies in cats under a variety of anesthetic conditions using the same electrodes and parameters of stimulation employed in the human studies to study the patterns of neuronal activity beneath the stimulating surface electrode. Whereas sufficiently strong currents can activate neurons within milliseconds, stimulating currents close to threshold activate sustained neural activity only after at least 350-500 ms. When currents are close to threshold, some neurons are inhibited for several hundreds of millisecond before the balance between inhibition and excitation shifts towards excitation. These results suggest that the prolonged latencies, i.e., latencies beyond 200-250 ms, for the emergence of conscious experience following direct cortical stimulation result from a delay in the sustained activation of underlying cortical neurons at threshold currents rather than being due to any unusually long duration in central processing time. Intracellular records from cortical neurological cells during repetitive electrical stimulation of the surface of the feline striate cortex demonstrate that such stimulation induces a profound depolarizing shift in membrane potential that may persist after each stimulus train. Such a depolarization is evidence that extracellular K+ concentrations have increased during electrical stimulation. Such an increase in extracellular K+ progressively increases cortical excitability until the threshold for sustained activation of cortical neurons is reached and then exceeded. Consequently, the long latency for threshold activation of cortical neurons depends upon a dynamically increasing cortical facilatory process that begins hundreds of milliseconds before there is sustained activation of such neurons. In some cases, this facilatory process must overcome an initial stimulus-induced inhibition before neuronal firing commences. (shrink)

We argue that prediction success maximization is a basic objective of cognition and cortex, that it is compatible with but distinct from prediction error minimization, that neither objective requires subtractive coding, that there is clear neurobiological evidence for the amplification of predicted signals, and that we are unconvinced by evidence proposed in support of subtractive coding. We outline recent discoveries showing that pyramidal cells on which our cognitive capabilities depend usually transmit information about input to their basal dendrites and amplify (...) that transmission when input to their distal apical dendrites provides a context that agrees with the feedforward basal input in that both are depolarizing, i.e., both are excitatory rather than inhibitory. Though these intracellular discoveries require a level of technical expertise that is beyond the current abilities of most neuroscience labs, they are not controversial and acclaimed as groundbreaking. We note that this cellular cooperative context-sensitivity greatly enhances the cognitive capabilities of the mammalian neocortex, and that much remains to be discovered concerning its evolution, development, and pathology. (shrink)

In their environment, plants are continuously submitted to natural stimuli such as wind, rain, temperature changes, wounding, etc. These signals induce a cascade of events which lead to metabolic and morphogenetic responses. In this paper the different steps are described and discussed starting from the reception of the signal by a plant organ to the final morphogenetic response. In our laboratory two plants are studied: Bryonia dioica for which rubbing the internode results in reduced elongation and enhanced radial expansion and (...) Bidens pilosa for which the response occurs at distance, hence pricking the cotyledon of a plantlet induces the growth inhibition of both the hypocotyl and the axillary bud of the pricked cotyledon. Reception of the signal and transmission of the message. In Bryonia the signal is received by epidermal cells while in Bidens they are the cells adjacent to the midrib of the cotyledon which receive the mechanical signal. In both plants the message is transmitted via a wave of electric depolarization. This latter is composed of an action potential associated with a slow wave whose transmission rates are respectively 1cm s−1 and 1 mm s−1. Recent results have shown the involvement of Ca2+ in the triggering of the slow wave and the role of the H+ pump during the slow wave. Transient and fast biochemical responses. An entry of extraceilular Ca2+ into the cells and a transient increase in IP3 occur within seconds following the mechanical stimulus. At the same time, the membrane becomes more fluid, correlated with qualitative changes in phospholipids. The rapid increase in the concentration of peroxidated lipids may be correlated with ethylene biosynthesis which is stimulated after rubbing. Other parameters such as cytoplasmic pH, relative water content, hydric potential, membrane potential and modifications of K+, Mg2+-ATPase and Ca2+-ATPase activities, play a key role in the early responses induced by the traumatisms. Irreversible-biochemical responses. The mechanical stimulus performed on a Bryonia internode induces an acceleration of: i) enzymatic activities related to the lignification, ii) esterification of phenolic acids in the cell wall. Consequently the lignification process is accelerated. Storage of the information. After being received by the target cells the information can be stored during several days before being expressed. At the level of cotyledonary bud, the first message, previously stored, can be expressed or not by a second treatment. Bidens thus behaves as if it was able to “store” and to “retrieve” morphogenetic messages, using a sort of rudimentary memory. The nuclei of the bud cells of the pricked cotyledon show that these cells, initially in G2 phase, divide and then remain in the G1 phase. In Bryonia, calli derived from young stimulated internodes, keep thigmomorphogenetic characteristics during several weeks. In the last part of this paper the particularity of our plant model which permits a study of the transmission and storage of the message, is underlined. The links between the different steps induced by the stimulus are discussed. Special attention is devoted to second messengers and to the amplification of the message. (shrink)

Unlike other organs that operate continuously, such as the heart and kidneys, many of the operations of the nervous system shut down during sleep. The evolutionarily conserved unconscious state of sleep that puts animals at risk from predators indicates that it is an indispensable integral part of systems operation. A reasonable expectation is that any hypothesis for the mechanism of the nervous system functions should be able to provide an explanation for sleep. In this regard, the semblance hypothesis is examined. (...) Postsynaptic membranes are continuously being depolarized by the quantally released neurotransmitter molecules arriving from their presynaptic terminals. In this context, an incidental lateral activation of the postsynaptic membrane is expected to induce a semblance (cellular hallucination of arrival of activity from its presynaptic terminal, which forms a unit for internal sensation) of the arrival of activity from its presynaptic terminal as a systems property. This restricts induction of semblance to a context of a very high ratio of the duration of the default state of neurotransmitter-induced postsynaptic depolarization to the total duration of incidental lateral activations of the postsynaptic membrane. This requirement spans within a time-bin of a few sleep-wake cycles. Since the duration of quantal release remains maximized, the above requirement can be achieved only by ceiling the total duration of incidental lateral activations of the postsynaptic membrane, which necessitates a state of sleep. (shrink)

The neuroanatomical substrates controlling and regulating sleeping and waking, and thus consciousness, are located in the brain stem. Most crucial for bringing the brain into a state conducive for consciousness and information processing is the mesencephalic part of the brain stem. This part controls the state of waking, which is generally associated with a high degree of consciousness. Wakefulness is accompanied by a low-amplitude, high-frequency electroencephalogram, due to the fact that thalamocortical neurons fire in a state of tonic depolarization. (...) Information can easily pass the low-level threshold of these neurons, leading to a high transfer ratio. The complexity of the electroencephalogram during conscious waking is high, as expressed in a high correlation dimension. Accordingly, the level of information processing is high. Spindles, and alpha waves in humans, mark the transition from wakefulness to sleep. These phenomena are related to drowsiness, associated with a reduction in consciousness. Drowsiness occurs when cells undergo moderate hyperpolarizations. Increased inhibitions result in a reduction of afferent information, with a lowered transfer ratio. Information processing subsides, which is also expressed in a diminished correlation dimension. Consciousness is further decreased at the onset of slow wave sleep. This sleep is controlled by the medullar reticular formation and is characterized by a high-voltage, low-frequency electroencephalogram. Slow wave sleep becomes manifest when neurons undergo a further hyperpolarization. Inhibitory activities are so strong that the transfer ratio further drops, as does the correlation dimension. Thus, sensory information is largely blocked and information processing is on a low level. Finally, rapid eye movement sleep is regulated by the pontine reticular formation and is associated with a ''wake-like'' electroencephalographic pattern. Just as during wakefulness, this is the expression of a depolarization of thalamocortical neurons. The transfer ratio of rapid eye movement sleep has not yet been determined, but seems to vary. Evidence exists that this type of sleep, associated with dreaming, with some kind of perception and consciousness, is involved in processing of ''internal'' information. In line with this, rapid eye movement sleep has higher correlation dimensions than slow-wave sleep and sometimes even higher than wakefulness. It is assumed that the ''near-the-threshold'' depolarized state of neurons in the thalamus and cerebral cortex is a necessary condition for perceptual processes and consciousness, such as occurs during waking and in an altered form during rapid eye movement sleep. (shrink)

Evolution leads to more and more complex structures, e.g., molecules, cells and organisms. By means of such structures elementary dynamic bio-electrical fields originate in single cells. They further develop into neurons with neuronal fields, and these combine and integrate in brains into global neuro-electrical fields (NEF) as a medium for the fast representation of outer stimuli. The present hypothesis proposes a specific state of the global NEF in brains as the signature of consciousness. This NEF changes periodically between two states, (...) a de- and a hyperpolarized brain state, and these in turn are paralleled intimately by transitions between consciousness and unconsciousness. In the hyperpolarized state the elementary neuronal fields are ‘enslaved’ and synchronized by strong oscillations, and under these conditions the NEF is of low information capacity. In the depolarized state, however, the elementary fields are freed to self-organize and superimpose into an integrated NEF rich in information. In this condition the NEF acquires a qualitatively new state variable: consciousness. This new variable is no longer physically measurable; it can only be perceived by introspection. (shrink)

Hypoxia hampers ATP production and threatens cell survival. Since cellular energetics tightly controls cell responses and fate, ATP levels and dynamics are of utmost importance. An integrated mathematical model of ATP synthesis by the mitochondrial oxidative phosphorylation/electron transfer chain system has been recently published :e36, 2005). This model was validated under static conditions. To evaluate its performance under dynamical situations, we implemented and simulated it . Inner membrane potential and [NADH] were used as indicators of mitochondrial function. Root mean squared (...) error was used to compare simulations and experiments :39155–39165, 2003). Steady-state experimental data were reproduced within 2–6%. Model dynamics were evaluated under: baseline, activation of NADH production, addition of ADP, addition of inorganic phosphate, oxygen exhaustion. In all phases, except the last one, ΔΨ and [NADH] as well as oxygen consumption, were reproduced . Under anoxia, simulated ΔΨ markedly depolarized . In conclusion, the model reproduces dynamic data as long as oxygen is present. Anticipated improvement by the inclusion of ATP consumption and explicit Krebs cycle are under evaluation. (shrink)

Glutamate is the major excitatory neurotransmitter in the mammalian brain, with receptors on every neuron in the central nervous system; it has major roles in fast synaptic transmission and in the establishment of certain forms of memory. More than 20 years ago Olney and his colleagues(1) described the [Excitotoxic Hypothesis] which postulates that, in addition to its normal function in the healthy brain, glutamate can kill neurons by prolonged, receptorsmediated depolarization resulting in irreversible disturbances in ion homeostasis. Therefore, glutamate (...) is a two‐edged sword; in certain undefined, adverse conditions it undergoes a transition from neurotransmitter to neurotoxin. Its toxicity has been implicated in the death of neurons in ischemia, epilepsy, and the neurodegenerative disorders such as Alzheimer's, Huntington's, and Parkinson's diseases(2–5). Recent advances in the molecular cloning of the genes for the glutamate family of receptors has revealed a plethora of receptor subtypes and an unexpected level of complexity in the mechanisms of receptor expression and function. (shrink)

In the present study, we have demonstrated hysteresis phenomena in the excitability of single, enzymatically dissociated guinea pig ventricular myocytes. Membrane potentials were recorded with patch pipettes in the whole-cell current clamp configuration. Repetitive stimulation with depolarizing current pulses of constant cycle length and duration but varying strength led to predictable excitation (1:l) and non-excitation (1:0) patterns depending on current strength. In addition, transition between patterns depended on the direction of current intensity change and stable hysteresis loops were obtained in (...) stimulus:response pattern vs. current intensity plots in 14 cells. Increase of pulse duration and decrease of stimulation rate contributed to a reduction in hysteresis loop areas. Changes in amplitude and shape of the subthreshold responses during the transitions from one stable pattern to the other, suggested that activity led to an increase in membrane resistance, particularly in the voltage domain between resting potential, and threshold. Therefore, we modelled the dynamic behaviour of the single cells as a function of diastolic membrane resistance, using previously published analytical solutions. Numerical iteration of the analytical model equations closely reproduced the experimental hysteresis loops in both qualitative and quantitative ways. In particular, the effect of stimulation frequency on the model was similar to the experimental findings. The overall study suggests that the excitability pattern of guinea pig ventricular myocytes accounts for hysteresis and bistabilities when current intensity is allowed to fluctuate around threshold levels. (shrink)

Recommendation systems (RSs) predict what the user likes and recommend it to them. While at the onset of RSs, the latter was designed to maximize the recommendation accuracy (i.e., accuracy was their only goal), nowadays many RSs models include diversity in recommendations (which thus is a further goal of RSs). In the computer science community, the introduction of diversity in RSs is justified mainly through economic reasons: diversity increases user satisfaction and, in niche markets, profits.I contend that, first, the economic (...) justification of diversity in RSs risks reducing it to an empirical matter of preference; second, diversity is ethically relevant as it supports two autonomy rights of the user: the right to an open present and the right to be treated as an individual. So far, diversity in RSs has been morally defended only in the case of RSs of news and scholarly content: diversity is held to have a depolarizing effect in a democratic society and the scientific community and make the users more autonomous in their news choices. I provide a justification of diversity in RSs that embraces all kinds of RSs (i.e., a holistic moral defense) and is based on a normative principle founded on the agency of the user, which I call the right to be an exception to predictions. Such a right holds that the proper treatment of a RS user qua agent forbids providing them with recommendations based only on their past or similar users’ choices. (shrink)

Induction of c‐fos expression occurs following treatment of diverse cell types with agents that trigger mitogenesis, differentiation or membrane depolarization. We suggest that c‐fos may be regarded as a marker for a set of rapidly induced genes (termed cellular immediate‐early genes) whose function is to couple extracellular stimulation to long‐term responses. In the brain, these genes may contribute to the adaptive alterations involved in neuronal plasticity.

Short-term motor practice leads to plasticity in the primary motor cortex. The purpose of this study is to investigate the factors that determine the increase in corticospinal tract excitability after motor practice, with special focus on two factors; “the level of muscle activity” and “the presence/absence of a goal of keeping the activity level constant.” Fifteen healthy subjects performed four types of rapid thumb adduction in separate sessions. In the “comfortable task” and “forceful task”, the subjects adducted their thumb using (...) comfortable and strong forces. In the “comfortable with a goal task” and “forceful with a goal task”, subjects controlled the muscle activity at the same level as in the C and F, respectively, by adjusting the peak electromyographic amplitude within the target ranges. Paired associative stimulation, which combines peripheral nerve stimulation and transcranial magnetic stimulation, with an inter-stimulus interval of 25 ms was also done. Before and after the motor tasks and PAS25, TMS was applied to the M1. None of the four tasks showed any temporary changes in behavior, meaning no learning occurred. Motor-evoked potential amplitude increased only after the FG and it exhibited a positive correlation with the MEP increase after PAS25, suggesting that FG and PAS25 share at least similar plasticity mechanisms in the M1. Resting motor threshold decreased only after FG, suggesting that FG would also be associated with the membrane depolarization of M1 neurons. These results suggest task-dependent plasticity from the synergistic effect of forceful muscle activity and of setting a goal of keeping the activity level constant. (shrink)

This study investigated the neuromodulatory effects of transspinal stimulation on soleus H-reflex excitability and electromyographic activity during stepping in humans with and without spinal cord injury. Thirteen able-bodied adults and 5 individuals with SCI participated in the study. EMG activity from both legs was determined for steps without, during, and after a single-pulse or pulse train transspinal stimulation delivered during stepping randomly at different phases of the step cycle. The soleus H-reflex was recorded in both subject groups under control conditions (...) and following single-pulse transspinal stimulation at an individualized exactly similar positive and negative conditioning-test interval. The EMG activity was decreased in both subject groups at the steps during transspinal stimulation, while intralimb and interlimb coordination were altered only in SCI subjects. At the steps immediately after transspinal stimulation, the physiological phase-dependent EMG modulation pattern remained unaffected in able-bodied subjects. The conditioned soleus H-reflex was depressed throughout the step cycle in both subject groups. Transspinal stimulation modulated depolarization of motoneurons over multiple segments, limb coordination, and soleus H-reflex excitability during assisted stepping. The soleus H-reflex depression may be the result of complex spinal inhibitory interneuronal circuits activated by transspinal stimulation and collision between orthodromic and antidromic volleys in the peripheral mixed nerve. The soleus H-reflex depression by transspinal stimulation suggests a potential application for normalization of spinal reflex excitability after SCI. (shrink)

On the fictional level, La Route des Flandres deploys a world in the process of complete disintegration. The manifestly privileged situation is the debacle of the French army in 1940 in which a number of the novel's protagonists are involved: George, the narrator; his cousin, Captain de Reixach; Iglésia, previously the Captain's jockey, now his orderly; Blum, Wack, and their horses. The havoc wrought by the military debacle can be subdivided into five categories. With the dissociation and decimation of the (...) army . . . and the disintegration of the discipline which had consolidated it . . . an entire military order is in the course of demolition. The breakdown of the military organization is accompanied by a parallel dissolution of the social order. Scattered along the roads, the civilians have lost their essential function, their trade. And, in an incident which occurs in front of the captain, when a peasant threatens the deputy mayor with his hunting rifle, we detect a direct reversal of the civic order. In the mechanical order, the all but dismembered automobiles . . . and the dismantlement of their motors contribute to the general tide of dilapidation and decay. The spatial order, represented here by the traditional military space, endowed with significance and hierarchically divided into front and rear, becomes depolarized with the disappearance of the battle lines and the inextricable entanglement of the two armies . . . The temporal order, the chronological arrangement of events, is subject to a similar vitiation. Jean Ricardou is equally well known for his fiction, including L'Observatoire de Cannes , La Prise de Constantinople , Les Lieux-dits , and his criticism, including Problèmes du Nouveau Roman , Pour une Theorie du Nouveau Roman , and Le Nouveau Roman ."ARTISTS ON ART: Birth of a Fiction" appeared in the Winter 1977 issue of Critical Inquiry. Erica Freiberg regularly translates Jean Ricardou's works. She holds degrees in French and Italian, philosophy and modern literature from the University of Paris and the University of Geneva. (shrink)

On the fictional level, La Route des Flandres deploys a world in the process of complete disintegration. The manifestly privileged situation is the debacle of the French army in 1940 in which a number of the novel's protagonists are involved: George, the narrator; his cousin, Captain de Reixach; Iglésia, previously the Captain's jockey, now his orderly; Blum, Wack, and their horses. The havoc wrought by the military debacle can be subdivided into five categories. With the dissociation and decimation of the (...) army... and the disintegration of the discipline which had consolidated it... an entire military order is in the course of demolition. The breakdown of the military organization is accompanied by a parallel dissolution of the social order. Scattered along the roads, the civilians have lost their essential function, their trade. And, in an incident which occurs in front of the captain, when a peasant threatens the deputy mayor with his hunting rifle, we detect a direct reversal of the civic order. In the mechanical order, the all but dismembered automobiles... and the dismantlement of their motors contribute to the general tide of dilapidation and decay. The spatial order, represented here by the traditional military space, endowed with significance and hierarchically divided into front and rear, becomes depolarized with the disappearance of the battle lines and the inextricable entanglement of the two armies... The temporal order, the chronological arrangement of events, is subject to a similar vitiation. Jean Ricardou is equally well known for his fiction, including L'Observatoire de Cannes, La Prise de Constantinople, Les Lieux-dits, and his criticism, including Problèmes du Nouveau Roman, Pour une Theorie du Nouveau Roman, and Le Nouveau Roman."ARTISTS ON ART: Birth of a Fiction" appeared in the Winter 1977 issue of Critical Inquiry. Erica Freiberg regularly translates Jean Ricardou's works. She holds degrees in French and Italian, philosophy and modern literature from the University of Paris and the University of Geneva. (shrink)

In response to the intellectual movement of New Atheism, this volume articulates a "New Theist" response that has at its core a desire to engage in productive and depolarizing dialogue. To ensure this book is of interest to atheists and theists alike, a team of experts in the field of philosophy of religion offer an assessment of the strongest New Atheist arguments. The chapters address the most pertinent questions about God, including politics and morality, and each essay shows how a (...) reflective theist might deal with points raised by the New Atheists. This volume is a serious academic engagement with the questions asked by New Atheism. As such, it will be of significant interest to scholars working in the philosophy of religion and theology, as well as those engaged in religious studies generally. (shrink)