Zebrafish: Lead and Learning
Authors: Josephine Brenner, Maxmilian Ho, Jeremy Kaine, Alec Lau, Simon Ng, Richard Sear Adviser: Mary Haasch, Wauwatosa High School
Purpose: Adult zebrafish exposed to lead as embryos will exhibit lower learning and memory performance than adult zebrafish which were not exposed to lead as embryos.
Experiment: In collaboration with the Children's Environmental Health Sciences Center (CEHSC) at the University of Wisconsin-Milwaukee, students have tested the learning and memory capabilities of adult zebrafish exposed to 10uM lead as embryos, and adult zebrafish not exposed to lead as embryos. Using a simple T-maze, the number of trials needed for fish to learn to turn right (max. of 20 trials) and then learn the reverse by turning left (max. of 20 trials), was measured on three consecutive days and then 1 week after the initial day. Learning was measured by the number of trials needed to achieve 5 correct turns out of 6 consecutive trials. Memory was measured at 1 week using the same criteria.
Results: Adult zebrafish exposed to 10uM lead as embryos needed more trials to learn the right turn behavior compared to adult zebrafish not exposed to lead as embryos. Memories of learning the right turn in adult zebrafish exposed to 10uM lead as embryos needed a couple more trials compared to the adult zebrafish not exposed to lead as embryos.
Adult zebrafish exposed to 10uM lead as embryos needed more trials to learn the left turn behavior compared to the adult zebrafish not exposed to lead as embryos. Memory of learning the left turn at 1 week needed more trials by the adult zebrafish exposed to 10uM lead as embryos compared to the adult zebrafish not exposed to lead as embryos.
Conclusion: Lead exposure of zebrafish as embryos negatively affects learning as adults. Based on observations, students would like to compare the learning abilities of long finned to short finned zebrafish. Students would also like to pursue research into the affect of varying lengths of adult lead exposure on learning.