Media screen time use and mental health in school aged children during the pandemic.

BACKGROUND: Children's screen time activity has increased significantly during the pandemic. Extended school closures and heightened parent stress are associated with children's behavioural difficulties and time spent watching screens. The primary aim of this study was to determine which school and household factors were associated with challenging behaviours in Canadian schoolchildren during the COVID-19 pandemic. METHODS: This longitudinal survey study examined the association amongst screen time, internalizing and externalizing behaviours in school-aged children at two time points over the 2020-2021 academic school year. Parents completed survey measures on their parental involvement, stress levels, and their child's screen time use as well as their emotional and behavioural difficulties. RESULTS: Children's average daily screen time was 4.40 h (SE = 18.45) at baseline and 3.89 h (SE = 16.70) at 1-year follow up, with no significant change across the school year (p = .316). Increased screen time use was associated with a greater incidence of internalizing behaviours in children (p = .03). Children who spent more time on screens and who were in households with parents reporting higher stress levels had increased internalizing behaviours (p < .001). No association between screen time use and externalizing behaviours was evident; however, parent stress was positively associated with children's externalizing behaviours (p < .001). CONCLUSIONS: Children's screen time use has remained high during the pandemic and is associated with anxious and depressive symptoms. Children who spent more time on screens and who were in households with parents reporting higher stress levels had increased internalizing behaviours. Parent stress was positively associated with children's externalizing behaviours. Targeted family intervention plans focused on reducing parent stress and screen time use may aid in improving children's mental health during the ongoing pandemic.

Anxiety in children and youth with autism spectrum disorder and the association with amygdala subnuclei structure.

LAY ABSTRACT: Autism spectrum disorder (ASD) is clinically characterized by social communication difficulties as well as restricted and repetitive patterns of behavior. In addition, children with ASD are more likely to experience anxiety compared with their peers who do not have ASD. Recent studies suggest that atypical amygdala structure, a brain region involved in emotions, may be related to anxiety in children with ASD. However, the amygdala is a complex structure composed of heterogeneous subnuclei, and few studies to date have focused on how amygdala subnuclei relate to in anxiety in this population. The current sample consisted of 95 children with ASD and 139 non-autistic children, who underwent magnetic resonance imaging (MRI) and assessments for anxiety. The amygdala volumes were automatically segmented. Results indicated that children with ASD had elevated anxiety scores relative to peers without ASD. Larger basal volumes predicted greater anxiety in children with ASD, and this association was not seen in non-autistic children. Findings converge with previous literature suggesting ASD children suffer from higher levels of anxiety than non-autistic children, which may have important implications in treatment and interventions. Our results suggest that volumetric estimation of amygdala's subregions in MRI may reveal specific anxiety-related associations in children with ASD.

Joint attention in infants at high familial risk for autism spectrum disorder and the association with thalamic and hippocampal macrostructure.

Autism spectrum disorder (ASD) is a heritable neurodevelopmental disorder. Infants diagnosed with ASD can show impairments in spontaneous gaze-following and will seldom engage in joint attention (JA). The ability to initiate JA (IJA) can be more significantly impaired than the ability to respond to JA (RJA). In a longitudinal study, 101 infants who had a familial risk for ASD were enrolled (62% males). Participants completed magnetic resonance imaging scans at 4 or 6 months of age. Subcortical volumes (thalamus, hippocampus, amygdala, basal ganglia, ventral diencephalon, and cerebellum) were automatically extracted. Early gaze and JA behaviors were assessed with standardized measures. The majority of infants were IJA nonresponders (n = 93, 92%), and over half were RJA nonresponders (n = 50, 52%). In the nonresponder groups, models testing the association of subcortical volumes with later ASD diagnosis accounted for age, sex, and cerebral volumes. In the nonresponder IJA group, using regression method, the left hippocampus (B = -0.009, aOR = 0.991, P = 0.025), the right thalamus (B = -0.016, aOR = 0.984, P = 0.026), as well as the left thalamus (B = 0.015, aOR = 1.015, P = 0.019), predicted later ASD diagnosis. Alterations in thalamic and hippocampal macrostructure in at-risk infants who do not engage in IJA may reflect an enhanced vulnerability and may be the key predictors of later ASD development.

Three-Dimensional Atlas of the Human Amygdala Subnuclei Constructed Using Immunohistochemical and Ultrahigh-Field Magnetic Resonance Imaging Data.

The amygdala is central for social and emotional processing and has been implicated in various disorders including autism spectrum disorder (ASD) and Alzheimer's disease (AD). Animal research and some limited research with humans has indicated that widespread alterations in neuronal development or neuronal loss in the basolateral and other amygdala subnuclei may be a contributing factor to variations in social behaviours. Yet, the basolateral amygdala is comprised of three subnuclei, each with a specialized role related to the coordination of emotional regulation. Due to their small size, the nuclei which comprise the basolateral amygdala remain understudied in humans in vivo. In this work, we describe methodology to examine the basolateral amygdala and other subnuclei in human ex vivo medial temporal lobe prosections using ultrahigh-field magnetic resonance imaging (MRI) at 9.4 T. Manual segmentations of the amygdala subnuclei on MR images, verified with immunohistochemical data, provide a robust three-dimensional atlas of the human amygdala. The goal is to apply the atlas to in vivo MRI scans to examine basolateral amygdala macrostructural development attributed to social cognitive dysfunction in ASD and other neurodevelopmental disorders. Furthermore, the atlas can be used to examine MRI-based correlates of neuronal loss commonly seen in neurodegenerative disorders.

Amygdala subnuclei volumes and anxiety behaviors in children and adolescents with autism spectrum disorder, attention deficit hyperactivity disorder, and obsessive-compulsive disorder.

Alterations in the structural maturation of the amygdala subnuclei volumes are associated with anxiety behaviors in adults and children with neurodevelopmental and associated disorders. This study investigated the relationship between amygdala subnuclei volumes and anxiety in 233 children and adolescents (mean age = 11.02 years; standard deviation = 3.17) with autism spectrum disorder (ASD), attention deficit hyperactivity disorder (ADHD), and children with obsessive compulsive disorder (OCD), as well as typically developing (TD) children. Parents completed the Child Behavior Checklist (CBCL), and the children underwent structural MRI at 3 T. FreeSurfer software was used to automatically segment the amygdala subnuclei. A general linear model revealed that children and adolescents with ASD, ADHD, and OCD had higher anxiety scores compared to TD children (p < .001). A subsequent interaction analysis revealed that children with ASD (B = 0.09, p < .0001) and children with OCD (B = 0.1, p < .0001) who had high anxiety had larger right central nuclei volumes compared with TD children. Similar results were obtained for the right anterior amygdaloid area. Amygdala subnuclei volumes may be key to identifying children with neurodevelopmental disorders or those with OCD who are at high risk for anxiety. Findings may inform the development of targeted behavioral interventions to address anxiety behaviors and to assess the downstream effects of such interventions.

Determining the impact of unknown individuals in criminality using network analysis of DNA matches.

Criminal offenders missing from police files limit the capacity to reconstruct criminal networks for criminological research and operational purposes. Recent studies show that forensic DNA databanks offer potential to address this problem, through large-scale analysis of DNA matches, many of which involve unidentified offenders. Applying social network analysis (SNA) to 18 years of DNA match data from Québec, Canada, we found that 1400 unknowns do not occupy more marginal positions in the network than 13,000 known offenders, and explain up to 18% of SNA values (e.g., betweenness centrality) for the latter while supporting 46% of their clustering values. Our results contrast with previous studies, showing moreover that unknown individuals who are positioned centrally in a network may have a larger impact than previously expected on investigation policing with implications for forensic intelligence.

Early adversity and positive parenting: Association with cognitive outcomes in children with autism spectrum disorder.

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by impairments in social communication and repetitive behaviors. Children with ASD are statistically more likely to experience early adversity; however, little is known about the types of early adversity that place these children at risk, the role of parenting as a protective factor, and how this early life stress impacts cognitive outcomes. We assessed early adversity in 302 children (ASD = 98) aged 6-16 years old, using parent-based report. To identify protective factors, we assessed parenting styles using parent surveys. Executive functions were assessed in the children using the WISC-V. Children with ASD had an increased incidence of familial stressors compared to the typically developing (TD) group. Positive parenting was associated with a significant decrease in the incidence of familial adverse events for both children with ASD and TD children. Examining the relationship between adversity and cognitive outcomes, in young children (6-11 years) with ASD, environmental stressors were associated with cognitive impairments. Findings suggest children with ASD may be at higher risk for familial adversity than their TD peers. However, all children benefit from positive parenting styles, which may mitigate the adverse effects of family-based early life stress. LAY SUMMARY: Some key features of Autism Spectrum Disorder (ASD) include difficulties with communication and social impairments. This means that children with ASD may be more likely to experience early adversity (stressful social interactions which take place during childhood) than children without ASD. Research in typically developing (TD) children has shown that experiencing more stressful events in childhood can cause changes in the brain, which can potentially impact the child's memory, reasoning, and decision-making skills later in life. However, there is evidence to suggest that having a nurturing relationship with a parent can offset some of the negative impacts of childhood adversity. In our study, we found that children with ASD are more likely to experience family-related stress compared to TD children. Having a positive relationship with a parent, however, was linked to experiencing this type of stress less often for all children, regardless of whether they were diagnosed with ASD. We also found that stressors related to environmental factors like financial instability were associated with lower cognitive abilities in children with ASD under 12 years of age. Understanding how these factors interact and differ in children with ASD can help to build stronger families and help children with ASD to thrive throughout their development.

School's out: Parenting stress and screen time use in school-age children during the COVID-19 pandemic.

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 were associated with children's screen time during the pandemic, adjusting for demographic variables and daily activities. Results 104 parents were enrolled, and 73 (70.2%) parents completed the surveys. Children's screen time (e.g., watching television and playing video games) increased significantly, from 2.6 to 5.9h a day (p = .001) during pandemic-related school closures. Fewer changes in children's screen time use were significantly associated with greater 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 increased significantly during the initial months of the pandemic. Parent stress and parenting styles may be modifiable risk factors to promote children's well-being during the ongoing pandemic.

Peer victimization and the association with hippocampal development and working memory in children with ADHD and typically-developing children.

The symptoms of hyperactivity-impulsivity and inattention displayed by children with ADHD put them at risk of experiencing peer victimization. Hippocampal maturation, may reduce a child's vulnerability to the experience of peer victimization, as it has been associated with decreased ADHD symptomatology. Working memory is an important executive function in the formation and maintenance of social relationships, which is often impaired in ADHD. We aimed to evaluate the relationship between problem behaviours, peer victimization, hippocampal morphology, and working memory in children with and without ADHD. 218 typically-developing participants (50.5% male) and 232 participants diagnosed with ADHD (77.6% male) were recruited. The ADHD group was subdivided into inattentive (ADHD-I) or combined (ADHD-C) types. The Child Behavior Checklist measured problem behaviours and peer victimization. Children underwent Magnetic Resonance Imaging (MRI). Hippocampal subfield volumes were obtained using FreeSurfer. The Wechsler Intelligence Scale for Children-fifth edition measured working memory (WM). The ADHD-C group displayed significantly higher levels of problem behaviours and peer victimization (all, p < 0.001), compared to the other groups. Left Cornu Ammonis 3 (CA3) volume was a positive predictor of peer victimization (all, p < 0.013). Left CA3 volume was a positive predictor of WM and left Cornu Ammonis 4 (CA4) volume negatively predicted WM (all, p < 0.025). A cluster analysis revealed that children displaying symptoms of hyperactivity-impulsivity are the most at risk for peer victimization. Interventions focusing on minimizing peer victimization may aid in mitigating adverse downstream effects, and assist in promoting brain health and cognitive function.

Amygdala subnuclei development in adolescents with autism spectrum disorder: Association with social communication and repetitive behaviors.

INTRODUCTION: The amygdala subnuclei regulate emotional processing and are widely implicated in social cognitive impairments often seen in children with autism spectrum disorder (ASD). Dysregulated amygdala development has been reported in young children with ASD; less is known about amygdala maturation in later adolescence, a sensitive window for social skill development. METHODS: The macrostructural development of the amygdala subnuclei was assessed at two time points in a longitudinal magnetic resonance imaging (MRI) study of adolescents with ASD (n = 23) and typically-developing adolescents (n = 15) . In adolescents with ASD, amygdala subnuclei growth was assessed in relation to ASD symptomatology based on standardized diagnostic assessments. Participants were scanned with MRI at median age of 12 years and returned for a second scan at a median age of 15 years. The volumes of nine amygdala subnuclei were extracted using an automatic segmentation algorithm. RESULTS: When examining the longitudinal data acquired across two time points, adolescents with ASD had larger basolateral amygdala (BLA) nuclei volumes compared to typically developing adolescents (B = 46.8, p = 0.04). When examining ASD symptomatology in relation to the growth of the amygdala subnuclei, reciprocal social interaction scores on the ADI-R were positively associated with increased growth of the BLA nuclei (B = 8.3, p < 0.001). Growth in the medial nucleus negatively predicted the communication (B = -46.9, p = 0.02) and social (B = -47.7, p < 0.001) domains on the ADOS-G. Growth in the right cortical nucleus (B = 26.14, p = 0.02) positively predicted ADOS-G social scores. Central nucleus maturation (B = 29.9, p = 0.02) was associated with the repetitive behaviors domain on the ADOS-G. CONCLUSIONS: Larger BLA volumes in adolescents with ASD may reflect underlying alterations in cellular density previously reported in post-mortem studies. Furthermore, findings demonstrate an association between regional growth in amygdala subnuclei volumes and ASD symptomatology. Improved understanding of the developmental trajectories of the amygdala subnuclei may aid in identifying key windows for interventions, particularly for social communication, in adolescents with ASD.

STRmix™ put to the test: 300 000 non-contributor profiles compared to four-contributor DNA mixtures and the impact of replicates.

Probabilistic genotyping approaches are increasingly used for the interpretation of DNA mixtures. To explore the specificity of one of these systems (STRmix™), we conducted an extensive study using 24 complex mixtures: all were known or apparent 4-person mixtures with at least one contributor representing less than 20% of total DNA, and all mixtures had at least one contributor with suboptimal DNA quantity. Those mixtures were either generated in-house or from casework. All the mixtures were compared to 300,000 virtual non-contributors, resulting in a dataset of 7.2 million comparisons. The great majority of the non-contributor comparisons led to a LR lower than 1 for a specificity of 99.1%. The effect of using replicate amplifications to calculate the LR of non-contributors was also assessed as triplicates were used and led to an increased specificity of 99.8%. The very large extent of the analyzed data shows that STRmix™ has an excellent ability to discriminate non-contributors from complex DNA mixtures.

Repeatedly washed semen stains: Optimal screening and sampling strategies for DNA analysis.

In many sexual assault cases, bedding and clothing are essential pieces of evidence that are screened for semen stains to gather DNA from the assailant. In some cases, these items have been washed before being seized and sent to the forensic lab. However, few data exist on the optimal methods for detecting and sampling semen stains on washed fabrics. In this paper, we used semen stains washed up to six times to evaluate the efficiency of commonly used screening methods for the detection of semen: alternate light source (ALS), acid phosphatase (AP), prostate specific antigen (PSA) and microscopy (sperm Hy-Liter™, SHL). We also assessed different washing conditions (detergents, washing machines, addition of bleach) and sampling methods (cutting and swabbing). The results show that some semen stain detection strategies, such as ALS, PSA, and SHL, are effective even when the item was washed multiple times. We also show that a complete genetic profile could be obtained from semen stains washed six times. Based on these findings, we present different strategies for the detection and sampling of semen stains depending on the circumstances of the case.

Fetal alcohol spectrum disorders: Zebrafish in the analysis of the milder and more prevalent form of the disease.

Fetal Alcohol Spectrum Disorders (FASD) represent a large unmet medical need. Exposure of the developing human embryo to alcohol can lead to life-long suffering. Despite the well documented deleterious effects of alcohol on the developing fetus, pregnant women continue to drink alcohol, and FASD remains the leading cause of preventable mental retardation and other behavioral abnormalities. Particularly prevalent are the milder forms of the disease cluster, representing children who do not show obvious physical signs and who may be undiagnosed or misdiagnosed. To develop treatment and diagnostic tools, researchers have turned to animal models. The zebrafish is becoming one of the leading biomedical research organisms that may facilitate discovery of the biological mechanisms underlying this disease and the identification of biomarkers that may be used for diagnosis. Here we review the latest advances of this field, mostly focussing on the discoveries made in our own laboratory and others with zebrafish employed to analyze the effects of moderate to low level of exposure to alcohol. We argue that the zebrafish represents unique advantages, and adding information obtained with this species to the mix of other animal models will significantly increase translational relevance of animal biomedical research for the analysis of human FASD.

Effect of social isolation on anxiety-related behaviors, cortisol, and monoamines in adult zebrafish.

Social isolation can be used to study behavioral, neural, and hormonal mechanisms that regulate interactions in social animals. Although isolation effects have been reported in social mammals and various fish species, systematic studies with isolated zebrafish are rare. Here, the authors examined behavior (social and nonsocial), physiological stress (whole-body cortisol levels), and neurochemicals (serotonin, dopamine, and their metabolites), following acute and chronic social isolation in adult zebrafish. To observe how isolated fish respond behaviorally to social stimuli, they exposed zebrafish to live conspecifics or animated images after acute (24 hr) or chronic (6 months) social isolation. The authors observed that isolation did not affect locomotor activity, but acute isolation had weak nonsignificant anxiogenic effects in adult zebrafish. They also found that all isolated fish responded to both live and animated social stimuli, and the stress hormone, cortisol was lower in chronically isolated fish. Finally, neurochemical analyses showed that serotonin levels increased when fish were exposed to social stimulus after acute isolation, but its metabolite 5HIAA decreased in response to social stimulus following both acute and chronic isolation. Levels of both dopamine and its metabolite DOPAC were also reduced in fish exposed to social stimulus after acute and chronic isolation. Overall, these results show that isolation in zebrafish is an effective tool to study fundamental mechanisms controlling social interaction at behavioral and physiological levels. (PsycINFO Database Record

Zebrafish prefer larger to smaller shoals: analysis of quantity estimation in a genetically tractable model organism.

Numerical abilities have been demonstrated in a variety of non-human vertebrates. However, underlying biological mechanisms have been difficult to study due to a paucity of experimental tools. Powerful genetic and neurobiological tools already exist for the zebrafish, but numerical abilities remain scarcely explored with this species. Here, we investigate the choice made by single experimental zebrafish between numerically different shoals of conspecifics presented concurrently on opposite sides of the experimental tank. We examined this choice using the AB strain and pet store zebrafish. We found zebrafish of both populations to generally prefer the numerically larger shoal to the smaller one. This preference was significant for contrasted ratios above or equalling 2:1 (i.e. 4 vs. 0, 4 vs. 1, 8 vs. 2, 6 vs. 2 and 6 vs. 3). Interestingly, zebrafish showed no significant preference when each of the two contrasted shoals had at least 4 members, e.g. in a contrast 8 versus 4. These results confirm that zebrafish possess the ability to distinguish larger numbers of items from smaller number of items, in a shoaling context, with a potential limit above 4. Our findings confirm the utility of the zebrafish for the exploration of both the behavioural and the biological mechanisms underlying numerical abilities in vertebrates.

Behavioral Responses to Novelty or to a Predator Stimulus Are Not Altered in Adult Zebrafish by Early Embryonic Alcohol Exposure.

BACKGROUND: Fetal alcohol spectrum disorders (FASD) may vary in symptoms and severity. In the milder and more prevalent forms of the disease, behavioral abnormalities may include impaired social behavior, for example, difficulty interpreting social cues. Patients with FASD remain often undiagnosed due to lack of biomarkers, and treatment is unavailable because the mechanisms of the disease are not yet understood. Animal models have been proposed to facilitate addressing these problems. More recently, short exposure of the zebrafish embryo to low concentrations of alcohol was shown to lead to significant and lasting impairment of behavior in response to social stimuli. The impairment may be the result of abnormal social behavior or altered fear/anxiety. The goal of the current study was to investigate the latter. METHODS: Here, we employed the alcohol exposure regimen used previously (exposure of 24th hour postfertilization embryos to 0.00, 0.25, 0.50, 0.75, or 1.00% vol/vol alcohol for 2 hours), allowed the fish to reach adulthood, and measured the behavioral responses of these adults to a novel tank (anxiety-related behaviors) as well as to an animated image of a sympatric predator of zebrafish (fear-related behaviors). RESULTS: We found behavioral responses of embryonic alcohol-exposed adult fish to remain statistically indistinguishable from those of controls, suggesting unaltered anxiety and fear in the embryonic alcohol-treated fish. CONCLUSIONS: Given that motor and perceptual function was previously shown to be also unaltered in the adults after embryonic alcohol exposure, our current results suggest that the impaired response of these fish to social stimuli may be the result of abnormal social behavior.

DNA transfer during laundering may yield complete genetic profiles.

In a number of child sexual abuse cases, the alleged perpetrator is a member of the nuclear family. In those cases, there is a possibility that the suspect's DNA was innocently deposited onto the child's clothing without acts of sexual assault ever occurring, for example via secondary transfer within the washing machine. To assess the quantity and quality of DNA that may be transferred among clothing during laundering, we conducted three series of experiments. First, we evaluated the level of spermatozoa that may be transferred by washing pristine pairs of underwear with bed sheets containing a varying number of ejaculates. Secondly, we explored whether current genetic methods may also detect the transfer of DNA from vaginal secretions during a machine wash. Finally, we analyzed the background levels of DNA on children's underwear collected from control families where sexual abuse never occurred. For both spermatozoa and vaginal secretions, we revealed that sufficient amounts of DNA may transfer onto laundered clothing to yield complete genetic profiles. Furthermore, DNA from relatives living within the same household was found in most cuttings taken from control children's underwear. Based on these findings, we present a framework for the handling and interpretation of intrafamilial sexual abuse cases. These suggestions should help determine whether DNA was deposited directly onto a fabric or merely transferred during a wash.

Leading-edge forensic DNA analyses and the necessity of including crime scene investigators, police officers and technicians in a DNA elimination database.

In recent years, sophisticated technology has significantly increased the sensitivity and analytical power of genetic analyses so that very little starting material may now produce viable genetic profiles. This sensitivity however, has also increased the risk of detecting unknown genetic profiles assumed to be that of the perpetrator, yet originate from extraneous sources such as from crime scene workers. These contaminants may mislead investigations, keeping criminal cases active and unresolved for long spans of time. Voluntary submission of DNA samples from crime scene workers is fairly low, therefore we have created a promotional method for our staff elimination database that has resulted in a significant increase in voluntary samples since 2011. Our database enforces privacy safeguards and allows for optional anonymity to all staff members. We also offer information sessions at various police precincts to advise crime scene workers of the importance and success of our staff elimination database. This study, a pioneer in its field, has obtained 327 voluntary submissions from crime scene workers to date, of which 46 individual profiles (14%) have been matched to 58 criminal cases. By implementing our methods and respect for individual privacy, forensic laboratories everywhere may see similar growth and success in explaining unidentified genetic profiles in stagnate criminal cases.

Induction of social behavior in zebrafish: live versus computer animated fish as stimuli.

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.

An automated predator avoidance task in zebrafish.

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.