1,053 research outputs found

    Component Neural Systems for the Creation of Emotional Memories during Free Viewing of a Complex, Real-World Event

    Get PDF
    To investigate the neural systems that contribute to the formation of complex, self-relevant emotional memories, dedicated fans of rival college basketball teams watched a competitive game while undergoing functional magnetic resonance imaging (fMRI). During a subsequent recognition memory task, participants were shown video clips depicting plays of the game, stemming either from previously-viewed game segments (targets) or from non-viewed portions of the same game (foils). After an old–new judgment, participants provided emotional valence and intensity ratings of the clips. A data driven approach was first used to decompose the fMRI signal acquired during free viewing of the game into spatially independent components. Correlations were then calculated between the identified components and post-scanning emotion ratings for successfully encoded targets. Two components were correlated with intensity ratings, including temporal lobe regions implicated in memory and emotional functions, such as the hippocampus and amygdala, as well as a midline fronto-cingulo-parietal network implicated in social cognition and self-relevant processing. These data were supported by a general linear model analysis, which revealed additional valence effects in fronto-striatal-insular regions when plays were divided into positive and negative events according to the fan's perspective. Overall, these findings contribute to our understanding of how emotional factors impact distributed neural systems to successfully encode dynamic, personally-relevant event sequences

    Mouse frontal cortex mediates additive multisensory decisions

    Get PDF
    The brain can combine auditory and visual information to localize objects. However, the cortical substrates underlying audiovisual integration remain uncertain. Here, we show that mouse frontal cortex combines auditory and visual evidence; that this combination is additive, mirroring behavior; and that it evolves with learning. We trained mice in an audiovisual localization task. Inactivating frontal cortex impaired responses to either sensory modality, while inactivating visual or parietal cortex affected only visual stimuli. Recordings from >14,000 neurons indicated that after task learning, activity in the anterior part of frontal area MOs (secondary motor cortex) additively encodes visual and auditory signals, consistent with the mice's behavioral strategy. An accumulator model applied to these sensory representations reproduced the observed choices and reaction times. These results suggest that frontal cortex adapts through learning to combine evidence across sensory cortices, providing a signal that is transformed into a binary decision by a downstream accumulator

    A Neural Network Subgrid Model of the Early Stages of Planet Formation

    Full text link
    Planet formation is a multi-scale process in which the coagulation of ÎŒm\mathrm{\mu m}-sized dust grains in protoplanetary disks is strongly influenced by the hydrodynamic processes on scales of astronomical units (≈1.5×108 km\approx 1.5\times 10^8 \,\mathrm{km}). Studies are therefore dependent on subgrid models to emulate the micro physics of dust coagulation on top of a large scale hydrodynamic simulation. Numerical simulations which include the relevant physical effects are complex and computationally expensive. Here, we present a fast and accurate learned effective model for dust coagulation, trained on data from high resolution numerical coagulation simulations. Our model captures details of the dust coagulation process that were so far not tractable with other dust coagulation prescriptions with similar computational efficiency.Comment: 6 pages, 4 figures, accepted at the Machine Learning and the Physical Sciences workshop, NeurIPS 202

    The outsourcing of social care in Britain : what does it mean for voluntary sector workers?

    Get PDF
    While recent decades have witnessed a growth in the outsourcing of public services in Britain, the post-1997 UK Labour governments have sought to put in place mechanisms aimed at encouraging long-term collaborative contracting relationships marked by less reliance on cost-based competition. This article explores empirically how far these mechanisms have achieved their aims and thereby acted to protect the employment conditions of staff, and links this exploration to debates concerning the employment implications of organizational reforms within public sectors internationally. It concludes that in terms of bringing income security to the voluntary sector and stability to employment terms and conditions these efforts have been unsuccessful, and consequently casts doubts on more optimistic interpretations of the employment effects of organizational restructuring in the British public sector

    Low Fertility at the Turn of the Twenty-First Century

    Get PDF
    In the past few decades, demographic concerns have shifted from rapid population growth fueled by high fertility to concerns of population decline produced by very low, sub-replacement fertility levels. Once considered a problem unique to Europe or developed nations, concerns now center on the global spread of low fertility. Nearly half of the world's population now lives in countries with fertility at or below replacement levels. Further, by the mid-twenty-first century three of four countries now described as developing are projected to reach or slip below replacement fertility. We review the research on low fertility through the predominant frameworks and theories used to explain it. These explanations range from decomposition and proximate determinant frameworks to grand theories on the fundamental causes underlying the pervasiveness and spread of low fertility. We focus on the ability of theory to situate previous and future findings and conclude with directions for furthur research

    Effect of Angiotensin System Inhibitors on Physical Performance in Older People - A Systematic Review and Meta-Analysis

    Get PDF
    Objective: Preclinical and observational data suggest that angiotensin converting enzyme inhibitors (ACEi) and angiotensin receptor blockers (ARBs) may be able to improve physical performance in older people via direct and indirect effects on skeletal muscle. We aimed to summarize current evidence from randomised controlled trials in this area. Design: Systematic review and meta-analysis. Setting and Participants: Randomized controlled trials enrolling older people, comparing ACEi or ARB to placebo, usual care or another antihypertensive agent, with outcome data on measures of physical performance. Methods: We searched multiple electronic databases without language restriction between inception and the end of February 2020. Trials were excluded if the mean age of participants was <65 years or treatment was targeting specific diseases known to affect muscle function (for example heart failure). Data were sought on measures of endurance and strength. Standardized mean difference (SMD) treatment effects were calculated using random-effects models with RevMan software. Results: Eight trials (952 participants) were included. Six trials tested ACEi, 2 trials tested ARBs. The mean age of participants ranged from 66 to 79 years, and the duration of treatment ranged from 2 months to 1 year. Trials recruited healthy older people and people with functional impairment; no trials specifically targeted older people with sarcopenia. Risk of bias for all trials was low to moderate. No significant effect was seen on endurance outcomes [6 trials, SMD 0.04 (95% CI –0.22 to 0.29); P =.77; I2 = 53%], strength outcomes [6 trials, SMD –0.02 (95% CI –0.18 to 0.14), P =.83, I2 = 21%] or the short physical performance battery [3 trials, SMD –0.04 (95% CI –0.19 to 0.11), P =.60, I2 = 0%]. No evidence of publication bias was evident on inspection of funnel plots. Conclusions and Implications: Existing evidence does not support the use of ACE inhibitors or angiotensin receptor blockers as a single intervention to improve physical performance in older people
    • 

    corecore