Modeling the Transmission of the SARS-CoV-2 Delta Variant in a Partially Vaccinated Population

In a population with ongoing vaccination, the trajectory of a pandemic is determined by how the virus spreads in unvaccinated and vaccinated individuals that exhibit distinct transmission dynamics based on different levels of natural and vaccine-induced immunity. We developed a mathematical model that considers both subpopulations and immunity parameters, including vaccination rates, vaccine effectiveness, and a gradual loss of protection. The model forecasted the spread of the SARS-CoV-2 delta variant in the US under varied transmission and vaccination rates. We further obtained the control reproduction number and conducted sensitivity analyses to determine how each parameter may affect virus transmission. Although our model has several limitations, the number of infected individuals was shown to be a magnitude greater (~10×) in the unvaccinated subpopulation compared to the vaccinated subpopulation. Our results show that a combination of strengthening vaccine-induced immunity and preventative behavioral measures like face mask-wearing and contact tracing will likely be required to deaccelerate the spread of infectious SARS-CoV-2 variants.

No Evidence Against the Greater Male Variability Hypothesis: A Commentary on Harrison et al.’s Meta-Analysis of Animal Personality

Harrison et al. (2021) set out to test the greater male variability hypothesis with respect to personality in non-human animals. Based on the non-significant results of their meta-analysis, they concluded that there is no evidence to support the hypothesis, and that biological explanations for greater male variability in human psychological traits should be called into question. Here, we show that these conclusions are unwarranted. Specifically: (a) in mammals, birds, and reptiles/amphibians, the magnitude of the sex differences in variability found in the meta-analysis is entirely in line with previous findings from both humans and non-human animals; (b) the generalized lack of statistical significance does not imply that effect sizes were too small to be considered meaningful, as the study was severely underpowered to detect effect sizes in the plausible range; (c) the results of the meta-analysis can be expected to underestimate the true magnitude of sex differences in the variability of personality, because the behavioral measures employed in most of the original studies contain large amounts of measurement error; and (d) variability effect sizes based on personality scores, latencies, and proportions suffer from lac of statistical validity, adding even more noise to the meta-analysis. In total, Harrison et al.’s study does nothing to disprove the greater male variability hypothesis in mammals, let alone in humans. To the extent that they are valid, the data remain compatible with a wide range of plausible scenarios.

What Makes Behavioral Measures of Consciousness Subjective and Direct?

This article addresses two issues: the distinction between objective and subjective measures and the directness of such measures. It is argued that the distinction is unambiguous only when based on a methodological criterion (i.e. the threshold utilized by the measures) rather than a semantic one (i.e. their referring either to the world or to the participant’s inner states). Different senses of directness are discussed: metaphysical (which seems to rest on a category error), methodological (the only unambiguously defined one, though relating ‘directly’ to performance rather than awareness), semantic (which appears gradable), and causal.

On the interrelation between alcohol addiction–like behaviors in rats

Rationale Alcohol use disorder (AUD) is a complex, heterogeneous disorder that only occurs in a minority of alcohol users. Various behavioral constructs, including excessive intake, habit formation, motivation for alcohol and resistance to punishment have been implicated in AUD, but their interrelatedness is unclear. Objective The aim of this study was therefore to explore the relation between these AUD-associated behavioral constructs in rats. We hypothesised that a subpopulation of animals could be identified that, based on these measures, display consistent AUD-like behavior. Methods Lister Hooded rats (n = 47) were characterised for alcohol consumption, habit formation, motivation for alcohol and quinine-adulterated alcohol consumption. The interrelation between these measures was evaluated through correlation and cluster analyses. In addition, addiction severity scores were computed using different combinations of the behavioral measures, to assess the consistency of the AUD-like subpopulation. Results We found that the data was uniformly distributed, as there was no significant tendency of the behavioral measures to cluster in the dataset. On the basis of multiple ranked addiction severity scores, five animals (~ 11%) were classified as displaying AUD-like behavior. The composition of the remaining subpopulation of animals with the highest addiction severity score (9 rats; ~ 19%) varied, depending on the combination of measures included. Conclusion Consistent AUD-like behavior was detected in a small proportion of alcohol drinking rats. Alcohol consumption, habit formation, motivation for alcohol and punishment resistance contribute in varying degrees to the AUD-like phenotype across the population. These findings emphasise the importance of considering the heterogeneity of AUD-like behavior.

Electrophysiological and behavioral indicators of musical knowledge about unfamiliar music

Most listeners possess sophisticated knowledge about the music around them without being aware of it or its intricacies. Previous research shows that we develop such knowledge through exposure. This knowledge can then be assessed using behavioral and neurophysiological measures. It remains unknown however, which neurophysiological measures accompany the development of musical long-term knowledge. In this series of experiments, we first identified a potential ERP marker of musical long-term knowledge by comparing EEG activity following musically unexpected and expected tones within the context of known music (n = 30). We then validated the marker by showing that it does not differentiate between such tones within the context of unknown music (n = 34). In a third experiment, we exposed participants to unknown music (n = 40) and compared EEG data before and after exposure to explore effects of time. Although listeners’ behavior indicated musical long-term knowledge, we did not find any effects of time on the ERP marker. Instead, the relationship between behavioral and EEG data suggests musical long-term knowledge may have formed before we could confirm its presence through behavioral measures. Listeners are thus not only knowledgeable about music but seem to also be incredibly fast music learners.

Psychosocial Intervention for Youth With High Externalizing Behaviors and Aggression Is Associated With Improvement in Impulsivity and Brain Gray Matter Volume Changes

Background: Stop, Now And Plan (SNAP) is a cognitive behavioral-based psychosocial intervention that has a strong evidence base for treating youth with high aggression and externalizing behaviors, many of whom have disruptive behavior disorders. In a pre-post design, we tested whether SNAP could improve externalizing behaviors, assessed by the parent-rated Child Behavior Checklist (CBCL) and also improve behavioral measures of impulsivity in children with high aggression and impulsivity. We then investigated whether any improvement in externalizing behavior or impulsivity was associated with gray matter volume (GMV) changes assessed using structural magnetic resonance imaging (sMRI). We also recruited typically developing youth who were assessed twice without undergoing the SNAP intervention.Methods: Ten children who were participating in SNAP treatment completed the entire study protocol. CBCL measures, behavioral measures of impulsivity, and sMRI scanning was conducted pre-SNAP and then 13 weeks later post-SNAP. Twelve healthy controls also completed the study; they were rated on the CBCL, performed the same behavioral measure of impulsivity, and underwent sMRI twice, separated by 13 weeks. They did not receive the SNAP intervention.Result: At baseline, SNAP participants had higher CBCL scores and performed worse on the impulsivity task compared with the healthy controls. At the second visit, SNAP participants still had higher scores on the CBCL compared with normally-developing controls, but their performance on the impulsivity task had improved to the point where their results were indistinguishable from the healthy controls. Structural magnetic resonance imaging in the SNAP participants further revealed that improvements in impulsivity were associated with GMV changes in the frontotemporal region.Conclusion: These results suggest that SNAP led to improvement in behavioral measures of impulsivity in a cohort of boys with high externalizing behavior. Improvement in impulsivity was also associated with increased GMV changes. The mechanism behind these brain changes is unknown but could relate to cognitive behavioral therapy and contingency management interventions, important components of SNAP, that target frontotemporal brain regions. Clinically, this study offers new evidence for the potential targeting of brain regions by non-invasive modalities, such as repetitive transcranial magnetic stimulation, to improve externalizing behavior and impulsivity.

Study Title-Based Framing Effects on Reports of Sexual Violence Factors in College Students

Objective: There are many methodological issues in studying sexual violence, including potential framing effects. Framing effects refer to how researchers communicate the purpose of a study to par-ticipants, such as, how the study is advertised or explained. The aim of the current study was to inves-tigate if framing effects were associated with differences in participants’ self-reported experiences of sexual violence and related correlates. Methods: College students (N = 782) were recruited to par-ticipate in one of four identical studies that differed in the title: “Questionnaires about Alcohol,” “Questionnaires about Crime,” “Questionnaires about Health,” or “Questionnaires about Sexual As-sault.” Participants chose one of the four studies and completed measures of sexual violence as well as attitudinal and behavioral measures in randomized order. Results: We found significantly more reports of childhood sexual abuse (33.6% vs. 18.5%), rape (33.9% vs. 21.1%), higher frequency of vic-timization (M = 11.35 vs. 5.44), and greater acknowledged rape for bisexual people (46.2% vs. 0.0%) in the Sexual Assault condition compared to other conditions. There were no differences in sexual violence perpetration or attitudinal or behavioral measures. Conclusion: These results revealed that framing effects, based on the study title, affect outcomes in sexual victimization research. Rape was reported 1.6x more in the “Sexual Assault” condition than in the “Health” condition. It is unclear whether these framing effects reflect self-selection bias or framing related increased reports in the Sexual Assault condition, suppression of reports in other conditions, or a combination thereof.

Enhancing neural markers of attention in children with ADHD using a digital therapeutic

Attention deficit hyperactivity disorder (ADHD) is a prevalent neurodevelopmental condition characterized by diminished attentional control. Critically, these difficulties are related to negative consequences in real-life functioning both during development and into adulthood. There is now growing evidence that modulating the underlying neural circuits related to attention can improve behavior and brain function in children with ADHD. We have previously shown that game-based digital therapeutics targeting a key neural marker of attention–midline frontal theta (MFT)–yield positive effects on attentional control in several populations. However, the effects of such digital therapeutics in children with ADHD and no other comorbidities has not been yet examined. To address this gap, we assessed a sample of 25 children with ADHD (8–12 years old) on neural, behavioral, and clinical metrics of attention before and after a 4-week at-home intervention on an iPad targeting MFT circuitry. We found that children showed enhancements on a neural measure of attention (MFT power), as well as on objective behavioral measures of attention and parent reports of clinical ADHD symptoms. Importantly, we observed relationships between the neural and behavioral cognitive improvements, demonstrating that those children who showed the largest intervention-related neural gains were also those that improved the most on the behavioral tasks indexing attention. These findings provide support for using targeted, digital therapeutics to enhance multiple features of attentional control in children with ADHD. Study registration: ClinicalTrials.gov registry (NCT03844269) https://clinicaltrials.gov/ct2/show/NCT03844269.

Is the increased transmissibility of SARS-CoV-2 variants driven by within or outside-host processes?

Understanding the factors that increase the transmissibility of the recently emerging variants of SARS-CoV-2 can aid in mitigating the COVID-19 pandemic. The enhanced transmissibility could be attributed to enhanced within-host processes, such as contagiousness (viral shedding by an infected individual) and infectivity (the probability of a susceptible individual to get infected), or outside-host processes, such as viral stability on surfaces and in the air. We utilized a mathematical model in order to theoretically analyze the specific mechanisms of virus transfer between an infected and susceptible individual. This allowed us to examine how the within-host or outside-host processes affect the overall viral transmission. Our analysis is based the available data on the Alpha, Epsilon and Delta variants as well as the currently emerging Omicron variant. We found that the higher transmissibility of the SARS-CoV-2 variants can be attributed only to within-host processes. Specifically, enhanced contagiousness drives the Delta variant transmissibility, while the Alpha, Epsilon and Omicron are characterized by an enhanced infectivity. Since outside-host processes have little contribution to the observed increase in the transmissibility, leading stricter hygienic and behavioral measures than those that were already applied are not expected to achieve a pronounced mitigating effect.

A Multimodal Approach to Investigate the Neural Mechanisms of Real World Social Vision

Eye tracking and other behavioral measurements collected from patient-participants in their hospital rooms afford a unique opportunity to study immersive natural behavior for basic and clinical-translational research, and also requires addressing important logistical, technical, and ethical challenges. Hospital rooms provide the opportunity to richly capture both clinically relevant and ordinary natural behavior. As clinical settings, they add the potential to study the relationship between behavior and physiology by collecting physiological data synchronized to behavioral measures from participants. Combining eye-tracking, other behavioral measures, and physiological measurements enables clinical-translational research into understanding the participants' disorders and clinician-patient interactions, as well as basic research into natural, real world behavior as participants eat, read, converse with friends and family, etc. Here we describe a paradigm in individuals undergoing surgical treatment for epilepsy who spend 1-2 weeks in the hospital with electrodes implanted in their brain to determine the source of their seizures. This provides the unique opportunity to record behavior using eye tracking glasses customized to address clinically-related ergonomic concerns, synchronized direct neural recordings, use computer vision to assist with video annotation, and apply multivariate machine learning analyses to multimodal data encompassing hours of natural behavior. We discuss the acquisition, quality control, annotation, and analysis pipelines to study the neural basis of real world social and affective perception during natural conversations with friends and family in participants with epilepsy. We also discuss clinical, logistical, and ethical and privacy considerations that must be addressed to acquire high quality multimodal data in this setting.