The shaky foundations of simulating single-cell RNA sequencing data

BACKGROUND: With the emergence of hundreds of single-cell RNA-sequencing (scRNA-seq) datasets, the number of computational tools to analyze aspects of the generated data has grown rapidly. As a result, there is a recurring need to demonstrate whether newly developed methods are truly performant-on their own as well as in comparison to existing tools. Benchmark studies aim to consolidate the space of available methods for a given task and often use simulated data that provide a ground truth for evaluations, thus demanding a high quality standard results credible and transferable to real data. RESULTS: Here, we evaluated methods for synthetic scRNA-seq data generation in their ability to mimic experimental data. Besides comparing gene- and cell-level quality control summaries in both one- and two-dimensional settings, we further quantified these at the batch- and cluster-level. Secondly, we investigate the effect of simulators on clustering and batch correction method comparisons, and, thirdly, which and to what extent quality control summaries can capture reference-simulation similarity. CONCLUSIONS: Our results suggest that most simulators are unable to accommodate complex designs without introducing artificial effects, they yield over-optimistic performance of integration and potentially unreliable ranking of clustering methods, and it is generally unknown which summaries are important to ensure effective simulation-based method comparisons

From learned value to sustained bias: how reward conditioning changes attentional priority

IntroductionAttentional bias to reward-associated stimuli can occur even when it interferes with goal-driven behavior. One theory posits that dopaminergic signaling in the striatum during reward conditioning leads to changes in visual cortical and parietal representations of the stimulus used, and this, in turn, sustains attentional bias even when reward is discontinued. However, only a few studies have examined neural activity during both rewarded and unrewarded task phases.MethodsIn the current study, participants first completed a reward-conditioning phase, during which responses to certain stimuli were associated with monetary reward. These stimuli were then included as non-predictive cues in a spatial cueing task. Participants underwent functional brain imaging during both task phases.ResultsThe results show that striatal activity during the learning phase predicted increased visual cortical and parietal activity and decreased ventro-medial prefrontal cortex activity in response to conditioned stimuli during the test. Striatal activity was also associated with anterior cingulate cortex activation when the reward-conditioned stimulus directed attention away from the target.DiscussionOur findings suggest that striatal activity during reward conditioning predicts the degree to which reward history biases attention through learning-induced changes in visual and parietal activities

Hunt–Vitell’s General Theory of Marketing Ethics Predicts “Attitude-Behaviour” Gap in Pro-environmental Domain

The inconsistency between pro-environmental attitudes and behaviours, known as the “attitude-behaviour” gap, is exceptionally pronounced in scenarios associated with “green” choice. The current literature offers numerous explanations for the reasons behind the “attitude-behaviour” gap, however, the generalisability of these explanations is complex. In addition, the answer to the question of whether the gap occurs between attitudes and intentions, or intentions and behaviours is also unknown. In this study, we propose the moral dimension as a generalisable driver of the “attitude-behaviour” gap and investigate its effectiveness in predicting attitudes, pro-environmental intentions and subsequent behaviours. We do so by using Hunt–Vitell’s moral philosophy-based framework of ethical decision-making, which conceptualises morality as the central decision-making parameter. The results from 557 US MTurk participants revealed that the manipulation of moral dimensions, specifically deontology and teleology, impacted ethical evaluation of presented dilemmas, however, failed to translate into subsequent intentions and behaviours. This finding suggests (i) that the moral dimension has an effect in shaping attitudes toward environmental issues, and (ii) that gap occurs between attitudes and intentions rather than intentions and behaviours. Further investigation of what strengthens and/or overrides the effects of the moral dimension would help understand the reasons why moral attitudes do not always translate into subsequent intentions and behaviours in the pro-environmental domain

P for Politics D for Dialogue: Reflections on Participatory Design with Children and Animals

Participatory Design strives to open up the decision-making process and empower all those who may be affected by design. This is opposed to Design as a non-participatory process, in which the power to make decisions is vested in the hands of one group to the possible detriment of others. In this paper we interrogate the nature, possibilities and limitations of Participatory Design through the perspective of Child Computer Interaction (CCI) and Animal Computer Interaction (ACI). Due to the cognitive and communication characteristics, and to the social and legal status of their participants, researchers in these communities have to contend with and challenge existing notions of participation and design. Thus, their theories and practices provide a lens through which the nature and goals of Participatory Design can be examined with a view to facilitating the development of more inclusive participatory models and practices

The format of children's mental images: Evidence from mental scanning.

This study examined the development and format of children's mental images. Children (4-, 5-, 6-7-, 8-9-, and 11-year-olds) and adults (N=282) viewed a map of a fictitious island containing various landmarks and two misleading signposts, indicating that some equidistant landmarks were different distances apart. Five-year-olds already revealed the linear time-distance scanning effect, previously shown in adults (Experiments 1 and 2): They took longer to mentally scan their image of the island with longer distances between corresponding landmarks, indicating the depictive format of children's mental images. Unlike adults, their scanning times were not affected by misleading top-down distance information on the signposts until age 8 (Experiment 1) unless they were prompted to the difference from the outset (Experiment 2). Findings provide novel insights into the format of children's mental images in a mental scanning paradigm and show that children's mental images can be susceptible to top-down influences as are adults'

The format of children’s mental images: Penetrability of spatial images

To investigate the format of mental images and the penetrability of mental imagery performance to top-down influences in the form of gravity information, children (4-, 6-, 8- and 10-year-olds) and adults (N = 112) performed mental rotation tasks. A linear increase in response time with rotation angle emerged at 6-years, suggesting that spatial properties are represented in children’s mental images. Moreover, 6-, 8-, and 10-year-olds, but not 4-year-olds or adults, took longer to respond to rotated stimuli pairs when gravity information was incongruent with the direction of rotation rather than congruent. Overall, findings suggest that in contrast to adults’, 6- to 10-year-olds’ mental rotation performance was penetrated by top-down information. This research (a) provides insight into the format of young children’s mental images and (b) shows that children’s mental rotation performance is penetrable by top-down influences

Altered Cortico-Subcortical Network After Adolescent Alcohol Exposure Mediates Behavioral Deficits in Flexible Decision-Making

Behavioral flexibility, the ability to modify behavior according to changing conditions, is essential to optimize decision-making. Deficits in behavioral flexibility that persist into adulthood are one consequence of adolescent alcohol exposure, and another is decreased functional connectivity in brain structures involved in decision-making; however, a link between these two outcomes has not been established. We assessed effects of adolescent alcohol and sex on both Pavlovian and instrumental behaviors and resting-state functional connectivity MRI in adult animals to determine associations between behavioral flexibility and resting-state functional connectivity. Alcohol exposure impaired attentional set reversals and decreased functional connectivity among cortical and subcortical regions-of-interest that underlie flexible behavior. Moreover, mediation analyses indicated that adolescent alcohol-induced reductions in functional connectivity within a subnetwork of affected brain regions statistically mediated errors committed during reversal learning. These results provide a novel link between persistent reductions in brain functional connectivity and deficits in behavioral flexibility resulting from adolescent alcohol exposure

Engaged in play: Seven-year-olds’ engagement with the play frame when playing with toy figures and their engagement with the fictional world of a video game

Children’s engagement in fictional worlds created when playing with toys and video games has received little research attention. We explored whether children’s engagement with the play frame when playing with toy figures was associated with their engagement with the virtual world in a video game in a community sample of 251 seven-year-olds (M = 6.95 years, SD = 0.38, 44 % girls). Using observational coding, we found that children’s engagement with the play frame by enacting roles ‘within’ the fictional world was positively associated with engaging with the virtual world in the video game. We also found that child characteristics, particularly children’s sex and their propensity to talk during play, were associated with their engagement in the two forms of play, and explained the associations in engagement between play contexts. These findings are discussed in terms of the features of the two contexts of play and how they promote children’s engagement with the fictional worlds

Acute phenylalanine/tyrosine depletion of phasic dopamine in the rat brain

Dopamine plays a critical role in striatal and cortical function, and depletion of the dopamine precursors phenylalanine and tyrosine is used in humans to temporarily reduce dopamine and probe the role of dopamine in behavior. This method has been shown to alter addiction-related behaviors and cognitive functioning presumably by reducing dopamine transmission, but it is unclear what specific aspects of dopamine transmission are altered