1,317 research outputs found
Minds and Brains, Sleep and Psychiatry
OBJECTIVE: This article offers a philosophical thesis for psychiatric disorders that rests upon some simple truths about the mind and brain. Specifically, it asks whether the dual aspect monismâthat emerges from sleep research and theoretical neurobiologyâcan be applied to pathophysiology and psychopathology in psychiatry. METHODS: Our starting point is that the mind and brain are emergent aspects of the same (neuronal) dynamics; namely, the brainâmind. Our endpoint is that synaptic dysconnection syndromes inherit the same dual aspect; namely, aberrant inference or belief updating on the one hand, and a failure of neuromodulatory synaptic gain control on the other. We start with some basic considerations from sleep research that integrate the phenomenology of dreaming with the neurophysiology of sleep. RESULTS: We then leverage this treatment by treating the brain as an organ of inference. Our particular focus is on the role of precision (i.e., the representation of uncertainty) in belief updating and the accompanying synaptic mechanisms. CONCLUSIONS: Finally, we suggest a dual aspect approachâbased upon belief updating (i.e., mind processes) and its neurophysiological implementation (i.e., brain processes)âhas a wide explanatory compass for psychiatry and various movement disorders. This approach identifies the kind of pathophysiology that underwrites psychopathologyâand points to certain psychotherapeutic and psychopharmacological targets, which may stand in mechanistic relation to each other
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Virtual reality and consciousness inference in dreaming
This article explores the notion that the brain is genetically endowed with an innate virtual reality generator that â through experience-dependent plasticity â becomes a generative or predictive model of the world. This model, which is most clearly revealed in rapid eye movement (REM) sleep dreaming, may provide the theater for conscious experience. Functional neuroimaging evidence for brain activations that are time-locked to rapid eye movements (REMs) endorses the view that waking consciousness emerges from REM sleep â and dreaming lays the foundations for waking perception. In this view, the brain is equipped with a virtual model of the world that generates predictions of its sensations. This model is continually updated and entrained by sensory prediction errors in wakefulness to ensure veridical perception, but not in dreaming. In contrast, dreaming plays an essential role in maintaining and enhancing the capacity to model the world by minimizing model complexity and thereby maximizing both statistical and thermodynamic efficiency. This perspective suggests that consciousness corresponds to the embodied process of inference, realized through the generation of virtual realities (in both sleep and wakefulness). In short, our premise or hypothesis is that the waking brain engages with the world to predict the causes of sensations, while in sleep the brainâs generative model is actively refined so that it generates more efficient predictions during waking. We review the evidence in support of this hypothesis â evidence that grounds consciousness in biophysical computations whose neuronal and neurochemical infrastructure has been disclosed by sleep research
Common sleep disorders in pregnancy: a review
In this review, we provide a comprehensive overview of common sleep disorders during pregnancy, including their characterization, prevalence, risk factors, and possible contribution to maternal and fetal outcomes. We conducted a quasi-systematic literature search of the MEDLINE database and identified 744 studies from 1991 through 2021, inclusive, that met our inclusion criteria. We synthesized the existing literature on sleep disorders during pregnancy and highlighted controversies, research gaps, and needed clinical developments. Our review covers a range of sleep disorders, including insomnia, obstructive sleep apnea, restless legs syndrome, and circadian rhythm disorders. We discuss the prevalence of these disorders in pregnancy and their potential impact on maternal and fetal health outcomes. We also explore the relationship between sleep disorders, pre-pregnancy comorbidities such as obesity, and pregnancy-related conditions such as gestational diabetes mellitus and preeclampsia. In addition to summarizing the existing literature on sleep disorders during pregnancy, we also highlight opportunities for further research in this area. We suggest that future studies should strive to employ validated and objective measurement tools for sleep disorders and prioritize utilization of longitudinal methods with participant follow-up through postpartum, mid-life, menopause, and beyond. We also put forward investigation into the impact of circadian rhythm disruption on reproductive physiology and early pregnancy outcomes as an area of important work. Overall, our review provides valuable insights on sleep and reproduction and into common sleep disorders during pregnancy and their potential impact on maternal and fetal health outcomes
Impact of maternal posture on fetal physiology in human pregnancy: a narrative review
In numerous medical conditions, including pregnancy, gravity and posture interact to impact physiology and pathophysiology. Recent investigations, for example, pertaining to maternal sleeping posture during the third trimester and possible impact on fetal growth and stillbirth risk highlight the importance and potential clinical implications of the subject. In this review, we provide an extensive discussion of the impact of maternal posture on fetal physiology from conception to the postpartum period in human pregnancy. We conducted a systematic literature search of the MEDLINE database and identified 242 studies from 1991 through 2021, inclusive, that met our inclusion criteria. Herein, we provide a synthesis of the resulting literature. In the first section of the review, we group the results by the impact of maternal posture at rest on the cervix, uterus, placenta, umbilical cord, amniotic fluid, and fetus. In the second section of the review, we address the impact on fetal-related outcomes of maternal posture during various maternal activities (e.g., sleep, work, exercise), medical procedures (e.g., fertility, imaging, surgery), and labor and birth. We present the published literature, highlight gaps and discrepancies, and suggest future research opportunities and clinical practice changes. In sum, we anticipate that this review will shed light on the impact of maternal posture on fetal physiology in a manner that lends utility to researchers and clinicians who are working to improve maternal, fetal, and child health
Insight and Dissociation in Lucid Dreaming and Psychosis
Dreams and psychosis share several important features regarding symptoms and underlying neurobiology, which is helpful in constructing a testable model of, for example, schizophrenia and delirium. The purpose of the present communication is to discuss two major concepts in dreaming and psychosis that have received much attention in the recent literature: insight and dissociation. Both phenomena are considered functions of higher order consciousness because they involve metacognition in the form of reflective thought and attempted control of negative emotional impact. Insight in dreams is a core criterion for lucid dreams. Lucid dreams are usually accompanied by attempts to control the dream plot and dissociative elements akin to depersonalization and derealization. These concepts are also relevant in psychotic illness. Whereas insightfulness can be considered innocuous in lucid dreaming and even advantageous in psychosis, the concept of dissociation is still unresolved. The present review compares correlates and functions of insight and dissociation in lucid dreaming and psychosis. This is helpful in understanding the two concepts with regard to psychological function as well as neurophysiology
Tax Evasion, Tax Avoidance and Tax Planning in Australia: The participation in mass-marketed tax avoidance schemes in the Pilbara region of Western Australia in the 1990s
This paper will examine the development of mass-marketed tax avoidance schemes in Australia. It will consider changes in approach to tax avoidance from the âbottom of the harbourâ schemes of the 1960s and 1970s to the mass-marketed tax avoidance schemes of the 1990s. It will examine the changing structure of tax avoidance from individually crafted tax avoidance structures designed by accountants and lawyers used by high wealth individuals to mass produced structures targeted at highly paid, and therefore highly taxed, blue collar workers in Australiaâs mining industry in the 1990s.
In the latter half of the twentieth century âunacceptableâ tax planning went from highly expensive, individually âtailor madeâ structures afforded and used only by the very wealthy, to inexpensive replicated structures marketed to skilled and unskilled tradespeople and labourers. By 1998 over 42 000 Australian taxpayers were engaged in tax avoidance schemes with the highest proportion focussed in the mining regions of Western Australia. In the remote and inhospitable mining community of Pannawonica, which has one of the highest paid workforces in Australia, the Australian Taxation Office identified that as many as one in five taxpayers were engaged in a mass-marketed tax avoidance scheme.
The paper will identify the causes of these changes, including the advent of the computerised information technology which permitted âmass productionâ of business structures designed to exploit business incentives in the Australian taxation system in the 1990s. It will also set these developments within the broader context of the tax compliance culture prevailing in Australia and overseas during this period
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