The zebrafish offers an excellent compromise between system complexity and practical simplicity and has been suggested as a translational research tool for the analysis of human brain disorders associated with abnormalities of social behavior. Unlike laboratory rodents zebrafish are diurnal, thus visual cues may be easily utilized in the analysis of their behavior and brain function. Visual cues, including the sight of conspecifics, have been employed to induce social behavior in zebrafish. However, the method of presentation of these cues and the question of whether computer animated images versus live stimulus fish have differential effects have not been systematically analyzed. Here, we compare the effects of five stimulus presentation types: live conspecifics in the experimental tank or outside the tank, playback of video-recorded live conspecifics, computer animated images of conspecifics presented by two software applications, the previously employed General Fish Animator, and a new application Zebrafish Presenter. We report that all stimuli were equally effective and induced a robust social response (shoaling) manifesting as reduced distance between stimulus and experimental fish. We conclude that presentation of live stimulus fish, or 3D images, is not required and 2D computer animated images are sufficient to induce robust and consistent social behavioral responses in zebrafish.

Background: During the COVID-19 pandemic, millions of children abruptly moved to online schooling, which required high levels of parental involvement. Family routines were disrupted, potentially increasing parental stress, and may be reflected in greater media screen time use in children. Objectives: To determine whether 1) parenting styles and 2) parenting stress were associated with children's screen time use during the pandemic compared to the pre-pandemic period. Methods: Parents (>18 years of age) were recruited to complete an online survey regarding changes in their children's (6-12 years) screen time use and daily activities before and during the pandemic. Stress and parental involvement were assessed using the Perceived Stress Scale (PSS) and Alabama Parenting Questionnaires respectively. General linear models assessed whether parenting style and parent stress was associated with children's screen time during the pandemic, adjusting for demographic variables and daily activities. Results: 104 parents were enrolled, and 78 (75%) parents completed the surveys. Children's screen time (e.g., watching television and playing video games) increased significantly, from 2.6 hours to 5.8 hours a day ( p=.001 ) during pandemic-related school closures. Smaller changes in children's screen time use were significantly associated with more parental involvement ( p=.017 ). Parent stress ( p=.018 ) significantly predicted children's screen time use. Lower household income was associated with increased hours of screen time in both models (both, p<.05 ). Conclusions: Children's screen time nearly doubled during the initial months of the pandemic. Parent stress and parenting styles may be modifiable risk factors to promote children's wellbeing during the ongoing pandemic.

Apolipoprotein D (apoD) and apolipoprotein E (apoE) are co-expressed in many tissues, and, in certain neuropathological situations, their expression appears to be under coordinate regulation. We have previously shown that apoD gene expression in cultured human fibroblasts is up-regulated when the cells undergo growth arrest. Here, we demonstrate that, starting around day 2 of growth arrest, both apoD and apoE mRNA levels increase between 1.5-and 27-fold in other cell types, including mouse primary fibroblasts and fibroblast-like and human astrocytoma cell lines. To understand the regulatory mechanisms of apoD expression, we have used apoD promoter-luciferase reporter constructs to compare gene expression in growing cells and in cells that have undergone growth arrest. Analysis of gene expression in cells transfected with constructs with deletions and mutations in the apoD promoter and constructs with artificial promoters demonstrated that the region between nucleotides ؊174 and ؊4 is fully responsible for the basal gene expression, whereas the region from ؊558 to ؊179 is implicated in the induction of apoD expression following growth arrest. Within this region, an alternating purine-pyrimidine stretch and a pair of serum-responsive elements (SRE) were found to be major determinants of growth arrest-induced apoD gene expression. Evidence is also presented that SREs in the apoE promoter may contribute to the up-regulation of apoE gene expression following growth arrest.

Zebrafish are becoming increasingly popular in behavioral neuroscience as investigators have started to realize the benefits of sophisticated genetic tools specifically developed for this species along with the pharmacological tools already available for other laboratory model organisms. The zebrafish has been proposed as an in vivo tool for the analysis of vertebrate fear responses as well as human psychopathological conditions such as anxiety. We have been developing behavioral tasks for zebrafish that could be utilized for screening mutation or drug induced changes in fear responses. In this paper we present a modified version of a previously developed predator avoidance paradigm that now allows the induction and quantification of avoidance reactions that we previously could not elicit. Most importantly, in the current paradigm zebrafish are now shown to respond to the appearance of a moving image of a sympatric predator, the Indian leaf fish, by increasing their distance from the image, a robust reaction that is easy to quantify in an automated manner. Unexpectedly, however, another fear response, the "diving" response, was seen robustly only at the beginning of the test but not in response to the predator stimulus. We discuss the implications of these results and conclude that although zebrafish fear responses are complex and context dependent, the current paradigm is a significant step towards high throughput screening for alterations in fear responses of zebrafish.

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