90 research outputs found
Tracy-Widom distribution in four-dimensional super-Yang-Mills theories
Various observables in different four-dimensional superconformal Yang-Mills
theories can be computed exactly as Fredholm determinants of truncated Bessel
operators. We exploit this relation to determine their dependence on the 't
Hooft coupling constant. Unlike the weak coupling expansion, which has a finite
radius of convergence, the strong coupling expansion is factorially divergent,
necessitating the inclusion of nonperturbative, exponentially small
corrections. We develop a method to systematically compute these corrections
and discuss the resurgent properties of the resulting transseries.Comment: 6 pages; v2: minor corrections and addition
Psychedelics, meditation, and self-consciousness
In recent years, the scientific study of meditation and psychedelic drugs has seen remarkable developments. The increased focus on meditation in cognitive neuroscience has led to a cross-cultural classification of standard meditation styles validated by functional and structural neuroanatomical data. Meanwhile, the renaissance of psychedelic research has shed light on the neurophysiology of altered states of consciousness induced by classical psychedelics, such as psilocybin and LSD, whose effects are mainly mediated by agonism of serotonin receptors. Few attempts have been made at bridging these two domains of inquiry, despite intriguing evidence of overlap between the phenomenology and neurophysiology of meditation practice and psychedelic states. In particular, many contemplative traditions explicitly aim at dissolving the sense of self by eliciting altered states of consciousness through meditation, while classical psychedelics are known to produce significant disruptions of self-consciousness, a phenomenon known as drug-induced ego dissolution. In this article, we discuss available evidence regarding convergences and differences between phenomenological and neurophysiological data on meditation practice and psychedelic drug-induced states, with a particular emphasis on alterations of self-experience. While both meditation and psychedelics may disrupt self-consciousness and underlying neural processes, we emphasize that neither meditation nor psychedelic states can be conceived as simple, uniform categories. Moreover, we suggest that there are important phenomenological differences even between conscious states described as experiences of self-loss. As a result, we propose that self-consciousness may be best construed as a multidimensional construct, and that “self-loss,” far from being an unequivocal phenomenon, can take several forms. Indeed, various aspects of self-consciousness, including narrative aspects linked to autobiographical memory, self-related thoughts and mental time travel, and embodied aspects rooted in multisensory processes, may be differently affected by psychedelics and meditation practices. Finally, we consider long-term outcomes of experiences of self-loss induced by meditation and psychedelics on individual traits and prosocial behavior. We call for caution regarding the problematic conflation of temporary states of self-loss with “selflessness” as a behavioral or social trait, although there is preliminary evidence that correlations between short-term experiences of self-loss and long-term trait alterations may exist
The default-mode, ego-functions and free-energy: a neurobiological account of Freudian ideas
This article explores the notion that Freudian constructs may have neurobiological substrates. Specifically, we propose that Freud’s descriptions of the primary and secondary processes are consistent with self-organized activity in hierarchical cortical systems and that his descriptions of the ego are consistent with the functions of the default-mode and its reciprocal exchanges with subordinate brain systems. This neurobiological account rests on a view of the brain as a hierarchical inference or Helmholtz machine. In this view, large-scale intrinsic networks occupy supraordinate levels of hierarchical brain systems that try to optimize their representation of the sensorium. This optimization has been formulated as minimizing a free-energy; a process that is formally similar to the treatment of energy in Freudian formulations. We substantiate this synthesis by showing that Freud’s descriptions of the primary process are consistent with the phenomenology and neurophysiology of rapid eye movement sleep, the early and acute psychotic state, the aura of temporal lobe epilepsy and hallucinogenic drug states
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The Neuroscience of Meditation: Connecting Research With Doctrine on Attention
Psychological and neuroscientific research on meditation and mindfulness has developed quickly over the past twenty years. Most research studies have methodological flaws and ambiguous results. The purpose of this review is to discuss these major methodological flaws and to clear up these ambiguities. Since there are many components to meditation and mindfulness this review focuses primarily on the research done on attention and its regulation. To clear up the ambiguities this review analyses the psychological and neuroscientific results of modern meditation research on attention in the context of Buddhist doctrine on meditation. Common results such as increased activity in the PFC or ACC during meditation on attentional tasks or enhanced performance on the Attention Network Task (ANT) in conflict monitoring and alerting suggest that meditation helps attention performance and regulation. The analyses connects these results to the theory of “monkey mind” and concepts of non-attachment in Buddhist doctrine. The correlation between the two areas, scientific research and anthropological study, strongly supports the results of scientific research. Although the methodologies may be flawed and imperfect, the results are promising and the field of research on meditation positively correlates with religious doctrine
Experiences with Pharmacological Methods for the Lateralization of Temporal Epileptic Foci
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