Cognitive dysfunction in Alzheimer’s disease is caused by disturbances in neuronal circuits of the brain underpinned by synapse loss, neuronal dysfunction and neuronal death. Amyloid beta and tau protein cause these pathological changes and enhance neuroinflammation, which in turn modifies disease progression and severity. Vagal nerve stimulation, via activation of the locus coeruleus, results in the release of catecholamines in the hippocampus and neocortex, which can enhance synaptic plasticity and reduce inflammatory signalling. Vagal nerve stimulation has shown promise (...) to enhance cognitive ability in animal models. Research in rodents has shown that VNS can have positive effects on basal synaptic function and synaptic plasticity, tune inflammatory signalling, and limit the accumulation of amyloid plaques. Research in humans with invasive and non-invasive VNS devices has shown promise for the modulation of cognition. However, the direct stimulation of the vagus nerve afforded with the invasive procedure carries surgical risks. In contrast, non-invasive VNS has the potential to be a broadly available therapy to manage cognitive symptoms in early AD, however, the magnitude and specificity of its effects remains to be elucidated, and the non-inferiority of the effects of non-invasive VNS as compared with invasive VNS still needs to be established. Ongoing clinical trials with healthy individuals and patients with early AD will provide valuable information to clarify the potential benefits of non-invasive VNS in cognition and AD. Whether invasive or non-invasive VNS can produce a significant improvement on memory function and whether its effects can modify the progression of AD will require further investigation. (shrink)

Since the Nuremberg trials (1947–1949), informed consent has become central for ethical practice in patient care and biomedical research. Codes of ethics emanating from the Nuremberg Code (1947) recognize the importance of protecting patients and research subjects from abuses, manipulation and deception. Informed consent empowers individuals to autonomously and voluntarily accept or reject participation in either clinical treatment or research. In some cases, however, the underlying mental or physical condition of the individual may alter his or her cognitive abilities and (...) compromise the informed consent process. This is particularly true in chronic psychiatric conditions such as Treatment-Resistant Depression (TRD), where individuals may fail to respond to traditional antidepressant treatments (e.g., psychotherapy, pharmacotherapy). Moreover, it may raise further concerns for an individual’s motivation to consent and the level of understanding of the treatment or research procedure. This paper focuses on the informed consent process for Vagus Nerve Stimulation (VNS) in the treatment of individuals diagnosed with TRD. Specifically, the paper addresses how depression may affect the decision-making capacity of an individual and the potential ethical and legal impact of failure to appreciate the seven elements of the consenting process (competence, voluntariness, disclosure, recommendation, understanding, decision, and authorization). To ensure the protection of vulnerable individuals with psychiatric disorders such as TRD and promote ethical behavior in biomedical research and patient care while avoiding potential legal pitfalls, we propose a paradigm that requires a stringent evaluation process of decision-making capacity for informed consent. (shrink)

Given its non-invasive nature, there is increasing interest in the use of transcutaneous vagus nerve stimulation across basic, translational and clinical research. Contemporaneously, tVNS can be achieved by stimulating either the auricular branch or the cervical bundle of the vagus nerve, referred to as transcutaneous auricular vagus nerve stimulation and transcutaneous cervical VNS, respectively. In order to advance the field in a systematic manner, studies using these technologies need to adequately report sufficient methodological detail (...) to enable comparison of results between studies, replication of studies, as well as enhancing study participant safety. We systematically reviewed the existing tVNS literature to evaluate current reporting practices. Based on this review, and consensus among participating authors, we propose a set of minimal reporting items to guide future tVNS studies. The suggested items address specific technical aspects of the device and stimulation parameters. We also cover general recommendations including inclusion and exclusion criteria for participants, outcome parameters and the detailed reporting of side effects. Furthermore, we review strategies used to identify the optimal stimulation parameters for a given research setting and summarize ongoing developments in animal research with potential implications for the application of tVNS in humans. Finally, we discuss the potential of tVNS in future research as well as the associated challenges across several disciplines in research and clinical practice. (shrink)

Given its non-invasive nature, there is increasing interest in the use of transcutaneous vagus nerve stimulation across basic, translational and clinical research. Contemporaneously, tVNS can be achieved by stimulating either the auricular branch or the cervical bundle of the vagus nerve, referred to as transcutaneous auricular vagus nerve stimulation and transcutaneous cervical VNS, respectively. In order to advance the field in a systematic manner, studies using these technologies need to adequately report sufficient methodological detail (...) to enable comparison of results between studies, replication of studies, as well as enhancing study participant safety. We systematically reviewed the existing tVNS literature to evaluate current reporting practices. Based on this review, and consensus among participating authors, we propose a set of minimal reporting items to guide future tVNS studies. The suggested items address specific technical aspects of the device and stimulation parameters. We also cover general recommendations including inclusion and exclusion criteria for participants, outcome parameters and the detailed reporting of side effects. Furthermore, we review strategies used to identify the optimal stimulation parameters for a given research setting and summarize ongoing developments in animal research with potential implications for the application of tVNS in humans. Finally, we discuss the potential of tVNS in future research as well as the associated challenges across several disciplines in research and clinical practice. (shrink)

Inhibitory control training is a promising method to improve individual performance of inhibitory control. Recent studies have suggested transcutaneous vagus nerve stimulation as a novel approach to affect cognitive function owing to its ability to modulate the locus coeruleus-noradrenaline system. To examine the synergistic effects of combining ICT with tVNS, 58 young males in college were randomly assigned to four groups: ICT + tVNS, ICT + sham tVNS, sham ICT + tVNS, and sham ICT + sham tVNS. Participants (...) were instructed to complete three sessions that comprised pre-training tests, a training session, and post-training tests sequentially. Results showed that the ICT + tVNS group significantly improved training and near-transfer effects on the stop-signal and Go/No-go tasks, and these effects were larger than those of the other groups. However, none of the groups exhibited the far-transfer effect on the color-word Stroop task. These results suggest that tVNS augments the intervention effects of training and similar inhibition tasks to achieve the synergistic effect; however, it does not modulate the effects of non-training tasks and obtain the far-transfer effect. ICT combined with tVNS may be a valuable intervention for improving IC in healthy individuals in certain industries and offers novel research ideas for using tVNS for cognitive improvement. (shrink)

Transcutaneous auricular vagus nerve stimulation, a non-invasive alternative to vagus nerve stimulation with implantable devices, has shown promise in treating disorders such as depression, migraine, and insomnia. Studies of these disorders with resting-state functional magnetic resonance imaging have found sustained changes in resting-state functional connectivity in patients treated with low frequency taVNS. A recent study has reported reductions in pain scores in patients with rheumatoid arthritis after a 12-week treatment of high-frequency sub-threshold taVNS. However, no studies (...) to date have examined the effects of high-frequency sub-threshold taVNS on rsFC. The objective of this study was to determine whether high-frequency sub-threshold taVNS induces changes in rsFC using seed regions from the cingulate cortex and insula, brain regions that play a key role in interoception and processing of pain. With a single-blind placebo-controlled repeated measures experimental design, rsfMRI scans were acquired before and after 15 min of either sub-threshold taVNS treatment or a sham control. Significant taVNS-related changes in functional connections to the cingulate cortex were detected between the anterior cingulate cortex and right superior temporal gyrus and between the midcingulate cortex and right inferior parietal lobule. In addition, significant changes in functional connections to the insula were detected between the posterior insula and right precuneus and between the anterior insula and right cuneus gyrus. These results suggest that high-frequency sub-threshold taVNS can lead to sustained effects on the rsFC of brain regions involved in interoception and processing of pain in a cohort of healthy subjects. This study lays the foundation for future rsfMRI studies of high-frequency sub-threshold taVNS in clinical populations. (shrink)

Closed-loop transcutaneous auricular vagal nerve stimulation was officially proposed in 2020. This work firstly reviewed two existing CL-taVNS forms: motor-activated auricular vagus nerve stimulation and respiratory-gated auricular vagal afferent nerve stimulation, and then proposed three future CL-taVNS systems: electroencephalography -gated CL-taVNS, electrocardiography -gated CL-taVNS, and subcutaneous humoral signals -gated CL-taVNS. We also highlighted the mechanisms, targets, technical issues, and patterns of CL-taVNS. By reviewing, proposing, and highlighting, this work might draw a preliminary blueprint for the development (...) of CL-taVNS. (shrink)

Recently a role for the vagus nerve in conditioning food preferences was established in rodents. In a prospective controlled clinical trial in humans, invasive vagus nerve stimulation shifted food choice toward lower fat content. Here we explored whether hedonic aspects of an orally sampled food stimulus can be modulated by non-invasive transcutaneous vagus nerve stimulation (tVNS) in humans. In healthy participants (n= 10, five women, 20–32 years old, no obesity) we tested liking and wanting (...) ratings of food samples with varying fat or sugar content with or without tVNS in a sham-controlled within-participants design. To determine effects of tVNS on food intake, we also measured voluntary consumption of milkshake. Spontaneous eye blink rate was measured as a proxy for dopamine tone. Liking of low-fat, but not high-fat puddings, was higher for tVNS relative to sham stimulation. Other outcomes showed no differences. These findings support a role for the vagus nerve promoting post-ingestive reward signals. Our results suggest that tVNS may be used to increase liking of low-calorie foods, which may support healthier food choices. (shrink)

Contemplative practices, such as meditation and yoga, are increasingly popular among the general public and as topics of research. Beneficial effects associated with these practices have been found on physical health, mental health, and cognitive performance. However, studies and theories that clarify the underlying mechanisms are lacking or scarce. This theoretical review aims to address and compensate this scarcity. We will show that various contemplative activities have in common that breathing is regulated or attentively guided. This respiratory discipline in turn (...) could parsimoniously explain the physical and mental benefits of contemplative activities through changes in autonomic balance. We propose a neurophysiological model that explains how these specific respiration styles could operate, by phasically and tonically stimulating the vagal nerve: respiratory vagal nerve stimulation. The vagal nerve, as a proponent of the parasympathetic nervous system, is the prime candidate in explaining the effects of contemplative practices on health, mental health, and cognition. We will discuss implications and limitations of our model. (shrink)

Microbes in the gastrointestinal tract are under selective pressure to manipulate host eating behavior to increase their fitness, sometimes at the expense of host fitness. Microbes may do this through two potential strategies: (i) generating cravings for foods that they specialize on or foods that suppress their competitors, or (ii) inducing dysphoria until we eat foods that enhance their fitness. We review several potential mechanisms for microbial control over eating behavior including microbial influence on reward and satiety pathways, production of (...) toxins that alter mood, changes to receptors including taste receptors, and hijacking of the vagus nerve, the neural axis between the gut and the brain. We also review the evidence for alternative explanations for cravings and unhealthy eating behavior. Because microbiota are easily manipulatable by prebiotics, probiotics, antibiotics, fecal transplants, and dietary changes, altering our microbiota offers a tractable approach to otherwise intractable problems of obesity and unhealthy eating. (shrink)

Cranial electrotherapy stimulation is a neuromodulation tool used for treating several clinical disorders, including insomnia, anxiety, and depression. More recently, a limited number of studies have examined CES for altering affect, physiology, and behavior in healthy, non-clinical samples. The physiological, neurochemical, and metabolic mechanisms underlying CES effects are currently unknown. Computational modeling suggests that electrical current administered with CES at the earlobes can reach cortical and subcortical regions at very low intensities associated with subthreshold neuromodulatory effects, and studies using electroencephalography (...) and functional magnetic resonance imaging show some effects on alpha band EEG activity, and modulation of the default mode network during CES administration. One theory suggests that CES modulates brain stem, limbic, and cortical regions and increases relative parasympathetic to sympathetic drive in the autonomic nervous system. There is no direct evidence supporting this theory, but one of its assumptions is that CES may induce its effects by stimulating afferent projections of the vagus nerve, which provides parasympathetic signals to the cardiorespiratory and digestive systems. In our critical review of studies using CES in clinical and non-clinical populations, we found severe methodological concerns, including potential conflicts of interest, risk of methodological and analytic biases, issues with sham credibility, lack of blinding, and a severe heterogeneity of CES parameters selected and employed across scientists, laboratories, institutions, and studies. These limitations make it difficult to derive consistent or compelling insights from the extant literature, tempering enthusiasm for CES and its potential to alter nervous system activity or behavior in meaningful or reliable ways. The lack of compelling evidence also motivates well-designed and relatively high-powered experiments to assess how CES might modulate the physiological, affective, and cognitive responses to stress. Establishing reliable empirical links between CES administration and human performance is critical for supporting its prospective use during occupational training, operations, or recovery, ensuring reliability and robustness of effects, characterizing if, when, and in whom such effects might arise, and ensuring that any benefits of CES outweigh the risks of adverse events. (shrink)

There is a paucity of treatment options for cognitively normal individuals with drug resistant genetic generalized epilepsy. Centromedian nucleus of the thalamus deep brain stimulation may be a viable treatment for GGE. Here, we present the case of a 27-year-old cognitively normal woman with drug resistant GGE, with childhood onset. Seizure semiology are absence seizures and generalized onset tonic clonic seizures. At baseline she had 4–8 GTC seizures per month and weekly absence seizures despite three antiseizure medications and vagus (...) nerve stimulation. A multidisciplinary committee recommended off-label use of CM DBS in this patient. Over 12-months of CM DBS she had two GTC seizure days, which were in the setting of medication withdrawal and illness, and no GTC seizures in the last 6 months. There was no significant change in the burden of absence seizures. Presently, just two studies clearly document CM DBS in cognitively normal individuals with GGE or idiopathic generalized epilepsy [in contrast to studies of cognitively impaired individuals with developmental and epileptic encephalopathies ]. Our results suggest that CM DBS can be an effective treatment for cognitively normal individuals with GGE and underscore the need for prospective studies of CM DBS. (shrink)

Maternal opioid use during pregnancy is a growing national problem and can lead to newborns developing neonatal opioid withdrawal syndrome soon after birth. Recent data demonstrates that nearly every 15 min a baby is born in the United States suffering from NOWS. The primary treatment for NOWS is opioid replacement therapy, commonly oral morphine, which has neurotoxic effects on the developing brain. There is an urgent need for non-opioid treatments for NOWS. Transcutaneous auricular neurostimulation, a novel and non-invasive form of (...) electrostimulation, may serve as a promising alternative to morphine. tAN is delivered via a multichannel earpiece electrode worn on and around the left ear, targeting two cranial nerves—the vagus and trigeminal nerves. Prior research suggests that auricular neurostimulation exerts an anxiolytic effect on the body by releasing endogenous opioids and reduces withdrawal symptoms in adults actively withdrawing from opioids. In this first-in-human prospective, open-label trial, we investigated tAN as an adjuvant to morphine therapy in eight infants >33 weeks gestational age suffering from NOWS and receiving oral morphine treatment. Infants received tAN for 30 min 1 h before receiving a morphine dose. tAN was delivered at 0.1 mA below perception intensity at two different nerve targets on the ear: Region 1, the auricular branch of the vagus nerve; and Region 2, the auriculotemporal nerve. tAN was delivered up to four times daily for a maximum of 12 days. The primary outcome measures were safety [heart rate monitoring, Neonatal Infant Pain Scale, and skin irritation] and morphine length of treatment. tAN was well-tolerated and resulted in no unanticipated adverse events. Comparing to the national average of 23 days, the average oral morphine LOT was 13.3 days and the average LOT after tAN initiation was 7 days. These preliminary data suggest that tAN is safe and may serve as a promising alternative adjuvant for treating NOWS and reducing the amount of time an infant receives oral morphine. (shrink)

Does exploration of the gut microbiota–brain axis expand our understanding of what it means to be human? Recognition and conceptualization of a gut microbiota–brain axis challenges our study of the nervous system. Here, integrating gut microbiota–brain research into the metaorganism model is proposed. The metaorganism—an expanded, dynamic unit comprising the host and commensal organisms—asserts a radical blurring between man and microbe. The metaorganism nervous system interacts with the exterior world through microbial‐colored lenses. Ongoing studies have reported that gut microbes contribute (...) to brain function and pathologies, even shaping higher neurological functions. How will continued collaborative efforts (e.g., between neurobiology and microbiology), including partnerships with the arts (e.g., philosophy), contribute to the knowledge of microbe‐to‐mind interactions? While this is not a systemic review, this nascent field is briefly described, highlighting ongoing challenges and recommendations for emerging gut microbiota–brain research. Also see the video abstract here https://youtu.be/lP9gOW8StXg. (shrink)

In Philip J. Ivanhoe’s introduction to his Readings from the Lu-Wang School of Neo-Confucianism, he argues convincingly that the Ming-era Neo-Confucian philosopher Wang Yang-ming (1472–1529) was much more influenced by Buddhism (especially Zen’s Platform Sutra) than has generally been recognized. In light of this influence, and the centrality of questions of selfhood in Buddhism, in this article I will explore the theme of selfhood in Wang’s Neo-Confucianism. Put as a mantra, for Wang “self-awareness is world-awareness.” My central image for this (...) mantra is the entire cosmos anthropomorphized as a doctor engaged in constant self-diagnosis, in which effort s/he is assisted by an entire staff of the nerves/nurses—individual humans enlightened as Wangian sages. In short, I will argue that the world for Wang could be meaningfully understood as a mindful, self-healing body within which humans are the sensitive nerves, using our mindful awareness to direct attention to the affected areas when injury or disease occurs. We are, and must thus recognize that we are, the bold but sensitive nervous system of the cosmos, sharing (like neurons) our loving excitement, carrying out (like a medical nurse) the doctor’s orders for the self-care of our cosmic body/medical corps. (shrink)

The Classical Theory of function in the nervous system postulates that the nerve impulse is the result of a sequential reversal of the membrane potential due to an increased permeability of the membrane, first to sodium ions, then to potassium ions. The new theory presents a bio-physical model which depicts the nerve impulse as an event involving the motions of electrons and waves, and their interactions with sodium and potassium atoms and ions. The velocity of the nerve (...) impulse (the most important parameter of nerve function) is determined by the product of two constants: c = the speed of light, which is a constant for all nerves; k =a constant for each nerve and is believed to be a specific property of nerve matter related in some way to the atomic process. The theory proposes that the nerve impulse in the axon is dualistic in nature (particles and waves play equally significant roles). The dualistic nature accounts for the three most fundamental characteristics of conduction of the nerve impulse: periodicity (conduction of a nerve impulse over long distances with constant velocity and form); non-summing (two nerve impulses cannot be in the same place at the same time); quantum nature of each nerve impulse — i.e., the unit message of the nerve impulse is an indivisible unit. (shrink)

Thomas Hobbes’ theory of punishment plays a constitutive role in the Leviathan’s theory of state sovereignty. Despite this, Hobbes’ justification for punishment is widely found to be discrepant, weak, inconsistent, and contradictory. Two dominant tendencies in the scholarship attempt to stabilize the Leviathan’s justification for the state’s right to punish by either identifying it with the sovereign’s right to war or by elaborating a theory of authorization within the state. In contrast, by tracing the deployments of the metaphor that Hobbes (...) utilizes to evoke the state’s right to punish in the Leviathan (i.e. that of the nerves of the Leviathan) this paper finds that these two accounts can be made to be consistent with each other — thereby destabilizing the grounds upon which the theory of punishment can be founded. (shrink)

In the literature investigating the long history of appeals to ‘nature’, in its multiple meanings, for rules of conduct or justification of social order, little attention has been paid to a long-standing tradition in which medical and physiological arguments merged into moral and social ones. A host of medical authors, biologists, social writers and philosophers assumed that nature spoke its moral language not only in its general economy, but also within and through the body. This is why, for instance, many (...) critics of Malthus argued that physiological self-regulating mechanisms ensured a spontaneous adaptation of fertility to the circumstances. Beliefs in a beneficent economy of nature persisted when Providence was replaced by evolution. To some, they provided reasons for hope even when others worried about ‘unfit’ members of society increasing at a quicker rate than ‘fit’ ones. The nerves gradually replaced food and blood as moral mediators between society and the body. When faith in bio-social progress was shaken by degeneration theories, and fin de siècle anxiety concerned underpopulation rather than overpopulation, not an insignificant proportion of those who emphasised the bad effects of modern civilisation resorted to ideas and arguments based on a view of the body in which physiology and morality worked together. A common language and common assumptions linked the Kulturpessimisten to their optimistic eighteenth-century colleagues, in spite of their different forecasts. The present paper traces continuities and discontinuities in the operation of a persistent set of interrelated ideas and assumptions on the coalescence of the physiological and the moral across disciplines and contexts. (shrink)

In the literature investigating the long history of appeals to ‘nature’, in its multiple meanings, for rules of conduct or justification of social order, little attention has been paid to a long-standing tradition in which medical and physiological arguments merged into moral and social ones. A host of medical authors, biologists, social writers and philosophers assumed that nature spoke its moral language not only in its general economy, but also within and through the body. This is why, for instance, many (...) critics of Malthus argued that physiological self-regulating mechanisms ensured a spontaneous adaptation of fertility to the circumstances. Beliefs in a beneficent economy of nature persisted when Providence was replaced by evolution. To some, they provided reasons for hope even when others worried about ‘unfit’ members of society increasing at a quicker rate than ‘fit’ ones. The nerves gradually replaced food and blood as moral mediators between society and the body. When faith in bio-social progress was shaken by degeneration theories, and fin de siècle anxiety concerned underpopulation rather than overpopulation, not an insignificant proportion of those who emphasised the bad effects of modern civilisation resorted to ideas and arguments based on a view of the body in which physiology and morality worked together. A common language and common assumptions linked the Kulturpessimisten to their optimistic eighteenth-century colleagues, in spite of their different forecasts. The present paper traces continuities and discontinuities in the operation of a persistent set of interrelated ideas and assumptions on the coalescence of the physiological and the moral across disciplines and contexts. (shrink)

In the literature investigating the long history of appeals to ‘nature’, in its multiple meanings, for rules of conduct or justification of social order, little attention has been paid to a long-standing tradition in which medical and physiological arguments merged into moral and social ones. A host of medical authors, biologists, social writers and philosophers assumed that nature spoke its moral language not only in its general economy, but also within and through the body. This is why, for instance, many (...) critics of Malthus argued that physiological self-regulating mechanisms ensured a spontaneous adaptation of fertility to the circumstances. Beliefs in a beneficent economy of nature persisted when Providence was replaced by evolution. To some, they provided reasons for hope even when others worried about ‘unfit’ members of society increasing at a quicker rate than ‘fit’ ones. The nerves gradually replaced food and blood as moral mediators between society and the body. When faith in bio-social progress was shaken by degeneration theories, and fin de siècle anxiety concerned underpopulation rather than overpopulation, not an insignificant proportion of those who emphasised the bad effects of modern civilisation resorted to ideas and arguments based on a view of the body in which physiology and morality worked together. A common language and common assumptions linked the Kulturpessimisten to their optimistic eighteenth-century colleagues, in spite of their different forecasts. The present paper traces continuities and discontinuities in the operation of a persistent set of interrelated ideas and assumptions on the coalescence of the physiological and the moral across disciplines and contexts. (shrink)

This article is about the beginnings of tissue culture-the culture of living, reproducing cells of complex organisms outside the body. It argues that Ross Harrison's experiments in nerve culture between 1907 and 1910 should be viewed as part of a larger shift in early twentieth-century laboratory practice from in vivo to in vitro experimentation. Via a focus on the temporality of experiment-contrasting the live object of Harrison's investigation with the static object of histological representations-this article details the production of (...) a new and surprising form of life, cellular life in vitro. Tissue culture, developed from Harrison's experiments, was greeted with great surprise and disbelief, despite Harrison's protestations that he had merely juxtaposed extant techniques. An analysis of these initial reactions to tissue culture illuminates the extent to which cells living visibly outside of the body in glass broke with in vivo practices and assumptions of the hiddenness and interiority of certain processes of growth and change. (shrink)

It was thus the combination of observational and experimental approaches that ultimately led to confirmation of the outgrowth theory. The observational method was essential for defining various possible methods of nerve fiber development. The multicellular, protoplasmic bridge and outgrowth theories were each postulated to explain purely observational evidence. However, the lack of truly suitable equipment and techniques to study the developing nervous system made it impossible to agree on a single theory on this basis alone. The experimental method provided (...) a means of choosing between these theories. Without the preceding observations that had led to the formulation of various hypotheses, however, the experimental approach might not have been so successful, for the power of this method is more of selection than of generation.Therefore it is impossible to weigh separately the contributions of the observational and experimental approaches to the question of nerve fiber development. Both were necessary for the ultimate acceptance of the outgrowth theory. *** DIRECT SUPPORT *** A8402051 00004. (shrink)

We investigate a recently devised polyhedral semantics for intermediate logics, in which formulas are interpreted in n-dimensional polyhedra. An intermediate logic is polyhedrally complete if it is complete with respect to some class of polyhedra. The first main result of this paper is a necessary and sufficient condition for the polyhedral completeness of a logic. This condition, which we call the Nerve Criterion, is expressed in terms of Alexandrov’s notion of the nerve of a poset. It affords a (...) purely combinatorial characterisation of polyhedrally complete logics. Using the Nerve Criterion we show, easily, that there are continuum many intermediate logics that are not polyhedrally complete but which have the finite model property. We also provide, at considerable combinatorial labour, a countably infinite class of logics axiomatised by the Jankov–Fine formulas of ‘starlike trees’ all of which are polyhedrally complete. The polyhedral completeness theorem for these ‘starlike logics’ is the second main result of this paper. (shrink)

Whereas many constructivist and feminist approaches to the social study of technology share an antipathy to technological tietenninism, they offer an insufficiently radical critique of technolagy. Three main problems in "anti-essentialist" critiques of techno logical determinism are identified, all of which mean that such critiques remain committed to a form of essentialism. These characteristics recur in many recent feminist arguments about technology, illustrated by the example of reproductive technologies. To overcome weaknesses in political radicalism based on anti-essentialism, it is necessary (...) to move to a "past-essentialist" approach. The unwillingness to do so is shown to be based on unfounded objections to "excessive" relativism. (shrink)