Developmental Methylmercury Exposure Affects Swimming Behavior and Foraging Efficiency of Yellow Perch (Perca flavescens) Larvae

Methylmercury (MeHg) is a pervasive and ubiquitous environmental neurotoxicant within aquatic ecosystems, known to alter behavior in fish and other vertebrates. This study sought to assess the behavioral effects of developmental MeHg exposure on larval yellow perch (Perca flavescens)--a nonmodel fish species native to the Great Lakes. Embryos were exposed to MeHg (0, 30, 100, 300, and 1000 nM) for 20 h and then reared to 25 days post fertilization (dpf) for analyses of spontaneous swimming, visual motor response (VMR), and foraging efficiency. MeHg exposures rendered total mercury (THg) body burdens of 0.02, 0.21, 0.95, 3.14, and 14.93 μg/g (wet weight). Organisms exposed to 1000 nM exhibited high mortality; thus, they were excluded from downstream behavioral analyses. All MeHg exposures tested were associated with a reduction in spontaneous swimming at 17 and 25 dpf. Exposure to 30 and 100 nM MeHg caused altered locomotor output during the VMR assay at 21 dpf, whereas exposure to 100 nM MeHg was associated with decreased foraging efficiency at 25 dpf. For the sake of comparison, the secondlowest exposure tested here rendered a THg burden that represents the permissible level of consumable fish in the United States. Moreover, this dose is reported in roughly two-thirds of consumable fish species monitored in the United States, according to the Food and Drug Administration. Although the THg body burdens reported here were higher than expected in the environment, our study is the first to analyze the effects of MeHg exposure on fundamental survival behaviors of yellow perch larvae and advances in the exploration of the ecological relevance of behavioral end points

Word learning from videos: evidence from 2-year-olds

Young children are exposed to large amounts of screen media daily and many parents believe educational media is a source of learning for their children. However, whether or not children are able to learn information from television and video is still inconclusive. Of specific interest in the current studies was whether or not children are able to learn words from television or videos. In Study 1, 2-year olds were introduced to a novel word through a short animated video and then tested to assess their ability to comprehend and produce the name of the word in both a video setting and a live setting. Study 2 examined 2-year olds ability to honor mutual exclusivity to words learned from videos using the same experimental tasks. The results suggest children are able to add a word learned from video to their productive vocabulary, transfer their knowledge of the word learned from video into their everyday setting, and apply the word learning principle of mutual exclusivity to words learned from videos. (Published By University of Alabama Libraries