Curiosity in zebrafish (Danio rerio)? Behavioral responses to 30 novel objects.

Curiosity-the motivation to seek out information-has been studied widely across the animal kingdom. To investigate curiosity in zebrafish we presented 30 novel objects to groups of zebrafish housed in semi-naturalistic tanks (6 tanks; 10 fish/tank; 10-min presentations). During the first 100 s and final 100 s of each object's 10-min presentation period, we recorded each group's: (i) latency to approach the object, (ii) attraction to the object, (iii) social dynamics: agonistic behavior and group cohesion and coordination, and (iv) diving behavior, a stress response in zebrafish. Comparing these behaviors to a 100 s baseline period when no object was present, we tested for neophobia (avoidance of novelty), neophilia (overall attraction to novelty), sustained interest (prolonged attraction to at least some presentations), discriminant interest (certain objects eliciting more attention than others), habituation (loss of interest over time), and alterations to social and stress behaviors. Zebrafish groups readily approached all objects (1 s median latency), were neophilic throughout all object presentations, and showed systematic sustained interest only for some object presentations at the beginning of the study (object presentations 1-10). Over the course of the study, zebrafish also showed signs of habituation such that by the final ten object presentations (21-30), there were no signs of overall sustained interest. During the beginning of the study (object presentations 1-10), we also found evidence for specific object-driven interest, with object ID accounting for 11% of the variability in interest scores (p < 0.01), and object-driven interest corresponding to alterations in social behavior: decreased aggression (p < 0.02), increased group cohesion (p < 0.02), and increased group coordination (p < 0.05). By explicitly investigating curiosity in fish, this work reveals that under certain conditions, zebrafish voluntarily engage in cognitive stimulation opportunities. More work is needed to clarify what types of information zebrafish find most rewarding and how long-term exposure to such opportunities may affect fish welfare.

Is Heightened-Shoaling a Good Candidate for Positive Emotional Behavior in Zebrafish?

Zebrafish, a highly-social species of freshwater fish, are widely studied across many fields of laboratory science including developmental biology, neuroscience, and genomics. Nevertheless, as standard housing for zebrafish typically consists of small and simplistic environments, less is known about their social behavioral repertoire in more naturalistic settings. In particular, spontaneously occurring, socio-positive affiliative behaviors (e.g., social coordination and cohesion) that may be indicative of positive emotional experiences have rarely been reported or studied deliberately in zebrafish. Housing adult zebrafish (10 fish/tank) in large semi-natural tanks (110 L; n = 6) with sloping gravel substrate, rocks, and artificial plants, we observed a previously undescribed behavior: Distinct periods of spontaneous, synchronized, compact aggregations, what we call "heightened-shoaling". This project aimed to quantify the characteristics of this distinctive behavior and compare parameters of heightened-shoaling to baseline periods (normal behavior) and pre-feed periods (feed-anticipatory behavior). First, across 4 days, we selected video-clips (100 s each) from within (i) instances of heightened-shoaling (n = 9), (ii) baseline periods (n = 18), and (iii) pre-feed periods (n = 18). For each of these video clips, we scan sampled every 10 s to determine fish orientations and location within the tank and agonistic behavior. Next, we used an all-occurrence sampling method to record the timing and duration of all episodes of heightened-shoaling behavior when tank-lights were on (8:00 h to 18:00 h) across 10 days. From the scan-sampling data, we found that compared to baseline periods, heightened-shoaling was characterized by increased shoal cohesion (p < 0.0001), increased adherence to the horizontal plane (p < 0.0001), decreased agonism (p < 0.0001), and no diving behavior (lower positions within the water column signal negative effect in zebrafish, p > 0.1). From the all-occurrence sampling data, we found 31 episodes of heightened-shoaling with instances observed in all six tanks and only a single case in which heightened-shoaling occurred in two tanks at the same time. The median episode duration was 7.6 min (Range 1.3⁻28.6). As the first systematic description of heightened-shoaling behavior, this research contributes to our knowledge of the range of zebrafish social dynamics living in naturalistic environments. Moreover, as a spontaneously occurring, protracted, affiliative behavior, heightened-shoaling appears to be a good candidate for future research into positive emotional behavior in zebrafish.

Comparison of Physiological and Psychological Responses to Exergaming and Treadmill Walking in Healthy Adults.

The purpose of this study was to compare treadmill walking with exergame play on the "EA Sports Active™" (Entertainment Arts, Redwood City, CA) for the Nintendo™ (Kyoto, Japan) Wii™. Thirty healthy adults (13 male, 17 female; 24.1±6.6 years old) spent 30 minutes walking briskly on a treadmill and approximately 40 minutes playing "Island Cardio Blast" on "EA Sports Active." Heart rate (HR) monitors, accelerometers, and Ratings of Perceived Exertion (RPE) were used to measure intensity. Participants also rated affect measures with the Feeling Scale and the Felt Arousal Scale and completed the Physical Activity Enjoyment Scale following completion of exercise. Participants had a significantly higher HR and RPE on the exergame but a higher percentage of minutes in moderate- or higher-intensity activity on the treadmill. Affect measures were consistent with past research, with positive affect following exercise in both conditions. Play on the "EA Sports Active" game for the Nintendo Wii elicited higher HR, RPE, and enjoyment measures than treadmill walking, indicating that it may be a good mode of exercise.

Do exergames allow children to achieve physical activity intensity commensurate with national guidelines?

The purpose of this study was to determine if two popular exergames, Wii Fit™ and EA Sports Active™, both games for the Nintendo Wii™ console, help children achieve intensity consistent with recommended physical activity guidelines. Thirty children (19 males and 11 females, Mean age = 9.4 ± 1.8 years) participated in this study by playing each game during one research session. During the session participants wore a heart rate monitor and accelerometer to measure exercise intensity. Perceived exertion (RPE) was measured with the children's run/walk OMNI scale. All three measures of exercise intensity (heart rate, accelerometer counts, and RPE) found that the EA Sports Active™ game session elicited higher exercise intensity. However, heart rate data found both games to achieve moderate intensity (65-68% age-predicted HRmax). When using heart rate as an indicator of exercise intensity it appears that both exergames were of sufficient intensity to achieve physical activity guidelines. Future studies should continue to investigate the utility of exergaming in helping children to become more physically active.