Feed-forward inhibition fine-tunes response timing in auditory-vocal interactions

The ability to regulate vocal timing is a fundamental aspect of communicative interactions for many species, including conversational speech among humans, yet little is known about the neural circuitry that regulates the input-dependent timing of vocal replies. Exploring this topic in the zebra finch premotor area HVC, we identify feed-forward inhibition as a key regulator of vocal response timing. Based on a spiking network model informed by behavioral and electrophysiological data from communicating zebra finches, we predicted that two different patterns of inhibition regulate vocal-motor responses. In one scenario, the strength of production-related premotor inhibition translates into plasticity in vocal response delays. In the other scenario, fast transient interneuron activity in response to auditory input results in the suppression of call production while a call is heard, thereby reducing acoustic overlap between callers. Extracellular recordings in HVC during the listening phase confirm the presence of auditory-evoked response patterns in putative inhibitory interneurons, along with corresponding signatures of auditory-evoked activity suppression. The proposed model provides a parsimonious framework to explain how auditory-vocal transformations can give rise to vocal turn-taking and highlights multiple roles of local inhibition for behavioral modulation at different time scales.

Individual and COVID-19-Specific Indicators of Compliance with Mask Use and Social Distancing: The Importance of Norms, Perceived Effectiveness and State Response

COVID-19 is a global pandemic that has resulted in widespread negative outcomes. Face masks and social distancing have been used to minimize its spread. Understanding who will engage in protective behaviors is crucial for continued response to the pandemic. We aimed to evaluate factors that are indicative of mask use and social distancing among current and former college students prior to vaccine access. Participants (N = 490; 67% female; 60% White) were current and former U.S. undergraduate college students. Perceived effectiveness and descriptive norms regarding COVID-19 safety measures, COVID-19-related news watching and seeking, state response timing to stay-at-home mandates, impulsivity-like traits, affect (mood), and demographic variables were assessed. Results found that greater perceived effectiveness indicated increased personal compliance within and across behaviors. Greater norms related to compliance within behaviors (e.g., indoor norms related to indoor compliance). Increased perceived stress, anxiety, and negative affect indicated greater compliance. More positive affect was associated with less compliance. Being non-White, compared to White (p < 0.001), and female, compared to male (p < 0.001), were associated with greater compliance. Overall, early implementation of stay-at-home orders, exposure to COVID-19-related news, and increased perceived effectiveness are crucial for health safety behavior compliance. Findings are important for informing response to health crises, including COVID-19.

Evaluation of China’s Hubei control strategy for COVID-19 epidemic: an observational study

Background To fight against COVID-19, many policymakers are wavering on stricter public health interventions. Examining the different strategies both in and out of China’s Hubei province, which contained the epidemic in late February 2020, could yield valuable guidance for the management of future pandemics. This study assessed the response process and estimated the time-varying effects of the Hubei control strategy. Analysis of these strategies provides insights for the design and implementation of future policy interventions. Methods We retrospectively compared the spread and control of COVID-19 between China’s Hubei (excluding Wuhan) and non-Hubei areas using data that includes case reports, human mobility, and public health interventions from 1 January to 29 February 2020. Static and dynamic risk assessment models were developed to statistically investigate the effects of the Hubei control strategy on the virus case growth after adjusting importation risk and policy response timing with the non-Hubei strategy as a control. Results The analysis detected much higher but differential importation risk in Hubei. The response timing largely coincided with the importation risk in non-Hubei areas, but Hubei areas showed an opposite pattern. Rather than a specific intervention assessment, a comprehensive comparison showed that the Hubei control strategy implemented severe interventions characterized by unprecedentedly strict and ‘monitored’ self-quarantine at home, while the non-Hubei strategy included physical distancing measures to reduce contact among individuals within or between populations. In contrast with the non-Hubei control strategy, the Hubei strategy showed a much higher, non-linear and gradually diminishing protective effect with at least 3 times fewer cases. Conclusions A risk-based control strategy was crucial to the design of an effective response to the COVID-19 outbreak. Our study demonstrates that the stricter Hubei strategy achieves a stronger controlling effect compared to other strategies. These findings highlight the health benefits and policy impacts of precise and differentiated strategies informed by constant monitoring of outbreak risk.

A unified model of the task-evoked pupil response

The pupil dilates and re-constricts following task events. It is popular to model this task-evoked pupil response as a linear transformation of event-locked impulses, the amplitudes of which are used as estimates of arousal. We show that this model is incorrect, and we propose an alternative model based on the physiological finding that a common neural input drives saccades and pupil size. The estimates of arousal from our model agreed with key predictions: arousal scaled with task difficulty and behavioral performance but was invariant to trial duration. Moreover, the model offers a unified explanation for a wide range of phenomena: entrainment of pupil size and saccade occurrence to task timing, modulation of pupil response amplitude and noise with task difficulty, reaction-time dependent modulation of pupil response timing and amplitude, a constrictory pupil response time-locked to saccades, and task-dependent distortion of this saccade-locked pupil response.

Trading Health for Wealth: The Effect of COVID-19 Response Stringency

International governments’ COVID-19 responses must balance human and economic health. Beyond slowing viral transmission, strict lockdowns have severe economic consequences. This work investigated response stringency, quantified by the Oxford COVID-19 Government Response Tracker’s Stringency Index, and examined how restrictive interventions affected infection rates and gross domestic product (GDP) in China and OECD countries. Accounting for response timing, China imposed the most stringent restrictions, while Sweden and Japan were the least stringent. Expected GDP declines range from −8% (Japan) to −15.4% (UK). While greater restrictions generally slowed viral transmission, they failed to reach statistical significance and reduced GDP (p = 0.006). Timing was fundamental: governments who responded to the pandemic faster saw greater reductions in viral transmission (p = 0.013), but worse decreases in GDP (p = 0.044). Thus, response stringency has a greater effect on GDP than infection rates, which are instead affected by the timing of COVID-19 interventions. Attempts to mitigate economic impacts by delaying restrictions or decreasing stringency may buoy GDP in the short term but increase infection rates, the longer-term economic consequences of which are not yet fully understood. As highly restrictive interventions were successful in some but not all countries, decision-makers must consider whether their strategies are appropriate for the country on health and economic grounds.

Time to Shine: Reliable Response-Timing Using R-Shiny for Online Experiments

Rising interest in online experiments for cognitive science research lies in the ability to reacha large number of participants in a short time at a relatively low cost. However, compared tocontrolled laboratory studies, online data is far more noisy. This is especially relevant whenreliable response-timing at a millisecond-level is paramount, as it is the case for manydecision-making tasks. In this paper we sought to replicate a well-validated cognitive effect-the distance effect in number comparisons- using an online mobile-friendly app developedwith open-source tools in R-Shiny. In this task, adapted from (Dehaene et al., 1990), participantshave to decide whether a number on the screen is larger or smaller than a standard (65 in ourstudy). The distance effect stands for the fact that response time (RT) is significantly larger asthe presented number is closer to the standard. A total of N=170 participants (110 with amobile device, 60 on a desktop computer) completed 116 trials over a ~7-minute session.Using generalized linear mixed models estimated with Bayesian inference methods, we founda numerical distance effect strikingly consistent with the original study. Furthermore, wereport systematic offsets in RTs that different OS, browsers and devices introduced. Ourresults demonstrate the reliability of R-Shiny for RT data collection. By doing so, our workpaves the ground for a seamless and robust implementation of simple cognitive tasks inonline studies over desktop and mobile devices using only R, a widely popular programmingframework among cognitive scientists.

A new genome allows the identification of genes associated with natural variation in aluminium tolerance in Brachiaria grasses

Toxic concentrations of aluminium cations and low phosphorus availability are the main yield-limiting factors in acidic soils, which represent half of the potentially available arable land. Brachiaria grasses, which are commonly sown as forage in the tropics because of their resilience and low demand for nutrients, show greater tolerance to high concentrations of aluminium cations (Al3+) than most other grass crops. In this work, we explored the natural variation in tolerance to Al3+ between high and low tolerant Brachiaria species and characterized their transcriptional differences during stress. We identified three QTLs (quantitative trait loci) associated with root vigour during Al3+ stress in their hybrid progeny. By integrating these results with a new Brachiaria reference genome, we identified 30 genes putatively responsible for Al3+ tolerance in Brachiaria. We observed differential expression during stress of genes involved in RNA translation, response signalling, cell wall composition, and vesicle location homologous to aluminium-induced proteins involved in limiting uptake or localizing the toxin. However, there was limited regulation of malate transporters in Brachiaria, which suggests that exudation of organic acids and other external tolerance mechanisms, common in other grasses, might not be relevant in Brachiaria. The contrasting regulation of RNA translation and response signalling suggests that response timing is critical in high Al3+-tolerant Brachiaria.

Evaluation of China's Hubei Control Strategy for COVID-19 Epidemic: An Observational Study

Background: To fight against COVID-19, many policymakers are wavering on stricter public health interventions. However, relying on these measures but different strategies, both in and out of China’s Hubei province basically contained the epidemic in late February 2020. This study aimed to assess the response process and estimate time-varying effect of Hubei control strategy to provide insights for intervention design and implementation.Methods: We retrospectively compared the spread and control of COVID-19 between China’s Hubei (excluding Wuhan) and non-Hubei areas using data that includes case reports, human mobility, and public health interventions from 1 January to 29 February, 2020. The static and dynamic risk assessment models were developed to statistically investigate the effect trends of Hubei control strategy on case growth after adjusting importation risk and response timing with non-Hubei strategy as a contrast.Results: The analysis detected much higher but differential importation risk in Hubei. The response timing largely coincided with the importation risk in non-Hubei areas, but Hubei areas showed an opposite pattern. A careful and comprehensive comparison showed that Hubei control strategy implemented interventions characterized by unprecedentedly strict and ‘monitored’ self-quarantine at home, while non-Hubei strategy included physical distancing measures to reduce contact among individuals within or between populations. In contrast with non-Hubei control strategy, Hubei strategy showed a much higher, non-linear and gradually diminishing protective effect with at least 3 times fewer cases.Conclusions: A risk-based control strategy is crucial to design an effective response for COVID-19 control. Our study demonstrates that the stricter Hubei strategy can achieve much better control effectiveness. These findings highlight the health benefits of precise and differentiated strategies informed by constant monitoring of outbreak risk and policy impacts.

Rotational dynamics versus sequence-like responses

In a recent review, Vyas et al. commented on our previous observations regarding the presence of response sequences in the activity of cortical neuronal population and the contribution of such sequences to rotational dynamics patterns revealed with jPCA. Vyas et al. suggested that rotations generated from sequence-like responses are different from the ones arising from empirical neuronal patterns, which are highly heterogeneous across motor conditions in terms of response timing and shape. Here we extend our previous findings with new results showing that empirical population data contain plentiful neuronal responses whose shape and timing persist across arm-movement conditions. The more complex, heterogeneous responses can be also found; these response patterns also contain temporal sequences, which are evident from the analysis of cross-condition variance. Combined with simulation results, these observations show that both consistent and heterogeneous responses contribute to rotational patterns revealed with jPCA. We suggest that the users of jPCA should consider these two contributions when interpreting their results. Overall, we do not see any principal contradiction between the neural population dynamics framework and our results pertaining to sequence-like responses. Yet, questions remain regarding the conclusions that can be drawn from the analysis of low-dimensional representations of neuronal population data.