250 research outputs found
Dynamic causal modelling revisited
Full text linkThis paper revisits the dynamic causal modelling of fMRI timeseries by replacing the usual (Taylor) approximation to neuronal dynamics with a neural mass model of the canonical microcircuit. This provides a generative or dynamic causal model of laminar specific responses that can generate haemodynamic and electrophysiological measurements. In principle, this allows the fusion of haemodynamic and (event related or induced) electrophysiological responses. Furthermore, it enables Bayesian model comparison of competing hypotheses about physiologically plausible synaptic effects; for example, does attentional modulation act on superficial or deep pyramidal cells - or both? In this technical note, we describe the resulting dynamic causal model and provide an illustrative application to the attention to visual motion dataset used in previous papers. Our focus here is on how to answer long-standing questions in fMRI; for example, do haemodynamic responses reflect extrinsic (afferent) input from distant cortical regions, or do they reflect intrinsic (recurrent) neuronal activity? To what extent do inhibitory interneurons contribute to neurovascular coupling? What is the relationship between haemodynamic responses and the frequency of induced neuronal activity? This paper does not pretend to answer these questions; rather it shows how they can be addressed using neural mass models of fMRI timeseries
KATRIN: Status and Prospects for the Neutrino Mass and Beyond
Full text linkThe Karlsruhe Tritium Neutrino (KATRIN) experiment is designed to measure a
high-precision integral spectrum of the endpoint region of T2 beta decay, with
the primary goal of probing the absolute mass scale of the neutrino. After a
first tritium commissioning campaign in 2018, the experiment has been regularly
running since 2019, and in its first two measurement campaigns has already
achieved a sub-eV sensitivity. After 1000 days of data-taking, KATRIN's design
sensitivity is 0.2 eV at the 90% confidence level. In this white paper we
describe the current status of KATRIN; explore prospects for measuring the
neutrino mass and other physics observables, including sterile neutrinos and
other beyond-Standard-Model hypotheses; and discuss research-and-development
projects that may further improve the KATRIN sensitivity.Comment: Contribution to Snowmass 2021. 70 pages excluding references; 35
figures. Author list updated June 202
Accumbal-thalamic connectivity and associated glutamate alterations in human cocaine craving: A state-dependent rs-fMRI and 1H-MRS study
Full text linkISSN:2213-158
The Effects of Low Doses of Lysergic Acid Diethylamide in Healthy Humans: Demystifying the Microdosing of Psychedelics
No full textCorrection: Synergistic, multi-level understanding of psychedelics: three systematic reviews and meta-analyses of their pharmacology, neuroimaging and phenomenology
No full textCorrection to: Translational Psychiatry https://doi.org/10.1038/s41398-024-03187-1, published online 04 December 2024
The meta-analysis of the 11-dimensional Altered States of Consciousness (11D-ASC) included three studies that contained duplicated data from other papers: Duerler et al. (2021), Lewis et al. (2017), and Preller et al. (2017). When these studies are removed from the analysis, the results are generally similar to the previously reported findings. Out of 33 comparisons (3 doses x 11 dimensions) between LSD and psilocybin, one becomes insignificant (insightfulness, medium dose), while one becomes more significant (disembodiment, medium dose). Note that the 5D-ASC meta-analysis did not include any duplicates, hence the results of that meta-analysis are unaffected.
We also wish to acknowledge two previous meta-analyses on the phenomenology of LSD and psilocybin, respectively, by Hirschfeld and colleagues:
1. Hirschfeld, T., Prugger, J., Majic, T., Schmidt, T.T. Dose-response relationships of LSD-induced subjective experiences in humans (2023). Neuropsychopharmacology, 48, 1602-1611.
2. Hirschfeld, T., Schmidt, T.T. Dose-response relationships of psilocybin-induced subjective experiences in humans (2021). Journal of Psychopharmacology. 35(4), 384-397.
The original article has been corrected
Finiteness and children with specific language impairment: an exploratory study
Full text linkChildren with specific language impairment (SLI) are well known for their difficulties in mastering the inflectional paradigms; in the case of learning German they also have problems with the appropriate verb position, in particular with the verb in second position. This paper explores the possibilities of applying a broader concept of finiteness to data from children with SLI in order to put their deficits, or rather their skills, into a wider perspective. The concept, as developed by Klein (1998, 2000), suggests that finiteness is tied to the assertion that a certain state of affairs is valid with regard to some topic time; that is, finiteness relates the propositional content to the topic component. Its realization involves the interaction of various grammatical devices and, possibly, lexical means like temporal adverbs. Furthermore, in the acquisition of finiteness it has been found that scope particles play a major role in both first- and second-language learning. The purpose of this paper is to analyze to what extent three German-learning children with SLI have mastered these grammatical and lexical means and to pinpoint the phase in the development of finiteness they have reached. The data to be examined are mostly narrative and taken from conversations and experiments. It will be shown that each child chooses a different developmental path to come to grips with the interaction of these devices
Psychedelic-Assisted Therapy for Substance Use Disorders and Potential Mechanisms of Action
Full text linkSubstance use disorders (SUD) represent a significant public health issue with a high need for novel and efficacious treatment options. In light of this high unmet need, recent results reporting beneficial outcomes of psychedelic-assisted therapy in SUD are particularly relevant. However, several questions remain with regard to this treatment approach. The clinical mechanisms of action of psychedelic substances in the treatment of SUD are not well understood. Closing this knowledge gap is critical to inform and optimize the psychotherapeutic embedding of the acute substance administration. In this chapter, we discuss potential mechanisms that have implications on psychotherapeutic approaches including induced neuroplasticity, alterations in brain network connectivity, reward and emotion processing, social connectedness, insight, and mystical experiences. Furthermore, we outline considerations and approaches that leverage these mechanisms in order to optimize the therapeutic embedding by maximizing synergy between substance effects and psychotherapy. Understanding the mechanisms of action, developing psychotherapeutic approaches accordingly, and evaluating their synergistic efficacy in scientific studies will be critical to advance the framework of psychedelic-assisted therapy for addiction, create evidence-based approaches, and achieve the best treatment outcome for patients with SUD
Modulation of Social Cognition via Hallucinogens and “Entactogens”
Full text linkSocial cognition is a fundamental ability in human everyday lives. Deficits in social functioning also represent a core aspect of many psychiatric disorders. Yet, despite its significance, deficits in social cognition skills are insufficiently targeted by current treatments. Hallucinogens and entactogens have been shown to have the potential to modulate social processing. This article reviews the literature on the influence of hallucinogens and entactogens on social processing in controlled experimental studies in humans and elucidates the underlying neurobiological and neuropharmacological mechanisms. Furthermore, it identifies current knowledge gaps and derives implications for hallucinogen-assisted treatment approaches as well as the development of novel medication for trans-diagnostic impairments in social cognition
Classical Psychedelics as Therapeutics in Psychiatry - Current Clinical Evidence and Potential Therapeutic Mechanisms in Substance Use and Mood Disorders
No full textClassical psychedelics, primarily psilocybin and lysergic acid diethylamide (LSD), have been used and extensively studied in Western medicine as part of substance-assisted psychotherapy in the 1950s and 1960s. Modern clinical research is currently gaining momentum and provides new evidence for the safety and efficacy of classical psychedelics (primarily psilocybin, but also LSD and ayahuasca) in the treatment of different psychiatric conditions, including substance use and mood disorders.In this review article, we outline common pathological mechanisms of substance use disorders (SUD) and unipolar depression. Next, the current literature on the effects of psychedelics is summarized in order to generate hypotheses regarding their potential therapeutic mechanisms of action in treating these psychiatric conditions. Finally, we review and discuss clinical trials published since 2011 investigating the effects of psychedelics in SUD and depression.While results from those modern clinical trials are promising, most of them do not meet the methodological requirements to allow firm conclusions on the clinical efficacy of psychedelics. Larger, blinded, randomized controlled trials (RCT) with clearly defined patient groups and well-defined primary endpoints are needed. Additionally, the therapeutic mechanisms of classical psychedelics are currently unknown. This review presents hypotheses derived from preclinical and human studies that need to be tested in future trials to better understand the clinical potential of psychedelic substances in modern psychiatry
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