Computational modeling has become an important tool in neuroscience and psychiatry research to provide insight into the cognitive processes underlying normal and pathological behavior. There are two ...modeling frameworks, reinforcement learning (RL) and drift diffusion modeling (DDM), that are well-developed in cognitive science, and have begun to be applied to Gambling Disorder. RL models focus on explaining how an agent uses reward to learn about the environment and make decisions based on outcomes. The DDM is a binary choice framework that breaks down decision making into psychologically meaningful components based on choice reaction time analyses. Both approaches have begun to yield insight into aspects of cognition that are important for, but not unique to, gambling, and thus relevant to the development of Gambling Disorder. However, these approaches also oversimplify or neglect various aspects of decision making seen in real-world gambling behavior. Gambling Disorder presents an opportunity for ‘bespoke’ modeling approaches to consider these neglected components. In this review, we discuss studies that have used RL and DDM frameworks to investigate some of the key cognitive components in gambling and Gambling Disorder. We also include an overview of Bayesian models, a methodology that could be useful for more tailored modeling approaches. We highlight areas in which computational modeling could enable progression in the investigation of the cognitive mechanisms relevant to gambling.
Abstract
We present blobcat, new source extraction software that utilizes the flood fill algorithm to detect and catalogue blobs, or islands of pixels representing sources, in 2D astronomical images. ...The software is designed to process radio-wavelength images of both Stokes I intensity and linear polarization, the latter formed through the quadrature sum of Stokes Q and U intensities or as a by-product of rotation measure synthesis. We discuss an objective, automated method by which estimates of position-dependent background root mean square noise may be obtained and incorporated into blobcat's analysis. We derive and implement within blobcat corrections for two systematic biases to enable the flood fill algorithm to accurately measure flux densities for Gaussian sources. We discuss the treatment of non-Gaussian sources in light of these corrections. We perform simulations to validate the flux density and positional measurement performance of blobcat, and we benchmark the results against those of a standard Gaussian fitting task. We demonstrate that blobcat exhibits accurate measurement performance in total intensity and, in particular, linear polarization. blobcat is particularly suited to the analysis of large survey data.
We present the third data release from the Australia Telescope Large Area Survey. These data combine the observations at 1.4 GHz before and after upgrades to the Australia Telescope Compact Array ...reaching a sensitivity of 14 μJy beam−1 in 3.6 deg2 over the Chandra Deep Field South (CDFS) and of 17 μJy beam−1 in 2.7 deg2 over the European Large Area ISO Survey South 1 (ELAIS-S1). We used a variety of array configurations to maximize the uv coverage resulting in a resolution of 16 by 7 arcsec in CDFS and of 12 by 8 arcsec in ELAIS-S1. After correcting for peak bias and bandwidth smearing, we find a total of 3034 radio source components above 5σ in CDFS, of which 514 (17 per cent) are considered to be extended. The number of components detected above 5σ in ELAIS-S1 is 2084, of which 392 (19 per cent) are classified as extended. The catalogues include reliable spectral indices (Δα < 0.2) between 1.40 and 1.71 GHz for ∼350 of the brightest components.
Pediatric posterior fossa tumors often present with hydrocephalus; postoperatively, up to 25% of patients develop cerebellar mutism syndrome. Arterial spin-labeling is a noninvasive means of ...quantifying CBF and bolus arrival time. The aim of this study was to investigate how changes in perfusion metrics in children with posterior fossa tumors are modulated by cerebellar mutism syndrome and hydrocephalus requiring pre-resection CSF diversion.
Forty-four patients were prospectively scanned at 3 time points (preoperatively, postoperatively, and at 3-month follow-up) with single- and multi-inflow time arterial spin-labeling sequences. Regional analyses of CBF and bolus arrival time were conducted using coregistered anatomic parcellations. ANOVA and multivariable, linear mixed-effects modeling analysis approaches were used. The study was registered at clinicaltrials.gov (NCT03471026).
CBF increased after tumor resection and at follow-up scanning (
= .045). Bolus arrival time decreased after tumor resection and at follow-up scanning (
= .018). Bolus arrival time was prolonged (
= .058) following the midline approach, compared with cerebellar hemispheric surgical approaches to posterior fossa tumors. Multivariable linear mixed-effects modeling showed that regional perfusion changes were more pronounced in the 6 children who presented with symptomatic obstructive hydrocephalus requiring pre-resection CSF diversion, with hydrocephalus lowering the baseline mean CBF by 20.5 (standard error, 6.27) mL/100g/min. Children diagnosed with cerebellar mutism syndrome (8/44, 18.2%) had significantly higher CBF at follow-up imaging than those who were not (
= .040), but no differences in pre- or postoperative perfusion parameters were seen.
Multi-inflow time arterial spin-labeling shows promise as a noninvasive tool to evaluate cerebral perfusion in the setting of pediatric obstructive hydrocephalus and demonstrates increased CBF following resolution of cerebellar mutism syndrome.
EMU: Evolutionary Map of the Universe
Publications of the Astronomical Society of Australia/Publications Astronomical Society of Australia
Journal Article
Abstract
A fully analytic statistical formalism does not yet exist to describe radio wavelength measurements of linearly polarized intensity that are produced using rotation measure synthesis. In ...this work we extend the analytic formalism for standard linear polarization, namely that describing measurements of the quadrature sum of Stokes Q and U intensities, to the rotation measure synthesis environment. We derive the probability density function and expectation value for Faraday-space polarization measurements for both the case where true underlying polarized emission is present within unresolved Faraday components, and for the limiting case where no such emission is present. We then derive relationships to quantify the statistical significance of linear polarization measurements in terms of standard Gaussian statistics. The formalism developed in this work will be useful for setting signal-to-noise ratio detection thresholds for measurements of linear polarization, for the analysis of polarized sources potentially exhibiting multiple Faraday components and for the development of polarization debiasing schemes.
Major depressive disorder is a significant and costly cause of global disability. Until the discovery of the rapid acting antidepressant (RAAD) effects of ketamine, treatments were limited to drugs ...that have delayed clinical benefits. The mechanism of action of ketamine is currently unclear but one hypothesis is that it may involve neuropsychological effects mediated through modulation of affective biases (where cognitive processes such as learning and memory and decision-making are modified by emotional state). Previous work has shown that affective biases in a rodent decision-making task are differentially altered by ketamine, compared to conventional, delayed onset antidepressants. This study sought to further investigate these effects by comparing ketamine with other NMDA antagonists using this decision-making task. We also investigated the subtype selective GluN2B antagonist, CP-101,606 and muscarinic antagonist scopolamine which have both been shown to have RAAD effects. Both CP-101,606 and scopolamine induced similar positive biases in decision-making to ketamine, but the same effects were not seen with other NMDA antagonists. Using targeted medial prefrontal cortex (mPFC) infusions, these effects were localised to the mPFC. In contrast, the GABA
agonist, muscimol, induced general disruptions to behaviour. These data suggest that ketamine and other RAADs mediate a specific effect on affective bias which involves the mPFC. Non-ketamine NMDA antagonists lacked efficacy and we also found that temporary inactivation of the mPFC did not fully recapitulate the effects of ketamine, suggesting a specific mechanism.
Ghrelin is a gut peptide that when acylated is thought to stimulate appetite. Circulating ghrelin concentrations could potentially be used as a predictor of DMI in cattle. The objective of this ...experiment was to determine the association of circulating ghrelin concentrations with DMI and other production traits. Steers and heifers were fed a finishing diet and individual intake was recorded for 84 d. Blood samples were collected via jugular venipuncture following the DMI and ADG measurement period. Plasma active ghrelin and total ghrelin were quantified using commercial RIA. Active ghrelin was not correlated to DMI (P = 0.36), but when DMI was modeled using a multivariate analysis including plasma metabolites and sex, active ghrelin was shown to be positively associated with DMI (P < 0.01) and contributed for 6.2% of the variation accounted for by the regression model (R2 = 0.33). Total ghrelin was negatively correlated to DMI (P < 0.01), but was not significant in a multivariate regression analysis (P = 0.13). The ratio of active:total ghrelin was positively associated with DMI (P < 0.01), and accounted for 10.2% of the variation in the model (R2 = 0.35). Active ghrelin was positively associated with ADG (P < 0.05), while total ghrelin was negatively associated with ADG (P < 0.01), and the ratio of active:total ghrelin was positively associated with ADG (P < 0.01). Active ghrelin was not associated with G:F (P = 0.88), but total ghrelin concentrations were negatively associated with G:F (P < 0.01) and accounted for 10.24% of the variation (R2 = 0.25). Heifers consumed less feed than steers (P < 0.01), tended to have greater active ghrelin concentrations (P = 0.06), and had greater total ghrelin concentrations than steers (P = 0.04). Total ghrelin concentrations were not different between sire breeds (P = 0.80), but active ghrelin concentrations and the ratio of active:total ghrelin differed between breeds (P < 0.01), indicating that genetics have an effect on the amount and form of circulating ghrelin. Total ghrelin concentrations tended (P = 0.08) to be correlated with HCW, but no other carcass characteristics were correlated with active or total ghrelin concentrations (P > 0.10). Results indicated that ghrelin concentrations are associated with DMI in beef cattle and that there is genetic variation that leads to differences in the amount and form of circulating ghrelin which could contribute to variation observed in DMI of beef cattle.
Reduced growth in utero is associated with type 2 (non-insulin-dependent) diabetes and impaired glucose tolerance in adult life. There is no direct evidence in human beings that maternal nutrition ...during gestation affects insulin-glucose metabolism. We investigated glucose tolerance in people born around the time of famine in the Netherlands during 1944–45.
We included 702 people born between Nov 1, 1943, and Feb 28, 1947, in Amsterdam, for whom we had detailed prenatal and birth records. We compared glucose and insulin responses to a standard oral glucose load in participants exposed to famine at any stage during gestation (exposed participants) with those who were born in the year before or conceived in the year after the famine (non-exposed participants).
Glucose concentrations were increased 2 h after a standard glucose load among exposed participants (p=0·006), and were highest in men and women exposed during mid and late gestation. Mean 2 h glucose concentration among non-exposed participants was 5·8 mmol/L; concentrations were 0·5 mmol/L (95% CI 0·1–0·9) higher among participants exposed during late gestation, 0·4 mmol/L (0–0·8) higher among those exposed during mid gestation, and 0·1 mmol/L (-0·4 to 0·6) among those exposed during early gestation. Participants born as thin babies to mothers with low bodyweights had the highest concentrations and concentrations were especially high among people exposed to famine who became obese as adults. Prenatal exposure to famine was related to increased fasting proinsulin (p=0·05) and 2 h insulin concentrations (p=0·04), which suggests an association with insulin resistance.
Prenatal exposure to famine, especially during late gestation, is linked to decreased glucose tolerance in adults. Poor nutrition in utero may lead to permanent changes in insulin-glucose metabolism, even if the effect on fetal growth is small. This effect of famine on glucose tolerance is especially important in people who become obese.
Determining magnetic field properties in different environments of the cosmic large-scale structure as well as their evolution over redshift is a fundamental step toward uncovering the origin of ...cosmic magnetic fields. Radio observations permit the study of extragalactic magnetic fields via measurements of the Faraday depth of extragalactic radio sources. Our aim is to investigate how much different extragalactic environments contribute to the Faraday depth variance of these sources. We develop a Bayesian algorithm to distinguish statistically Faraday depth variance contributions intrinsic to the source from those due to the medium between the source and the observer. In our algorithm the Galactic foreground and measurement noise are taken into account as the uncertainty correlations of the Galactic model. Additionally, our algorithm allows for the investigation of possible redshift evolution of the extragalactic contribution. This work presents the derivation of the algorithm and tests performed on mock observations. Because cosmic magnetism is one of the key science projects of the new generation of radio interferometers, we have predicted the performance of our algorithm on mock data collected with these instruments. According to our tests, high-quality catalogs of a few thousands of sources should already enable us to investigate magnetic fields in the cosmic structure.
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