The electric organ discharge (EOD) of the weakly electric fish Eigenmannia virescens and Gnathonemus petersii has been recorded and mapped in three-dimensional space using electrophysiological recording methods. The fish are available from aquarium stores and are not harmed by the investigation, making this exercise ideal for the high school classroom.
       This exercise familiarizes the class with the equipment and techniques used by electrophysiologists: preamplifiers, oscilloscopes, electrodes, grounding and shielding, and computer acquisition and analysis of data. Students learn basic neurophysiological concepts including muscle physiology, anatomy, biochemistry, membrane potential, sensory physiology, behavior, and evolution. The electric dipole created by the fish and the changes that occur when the fish encounter conductive and nonconductive substances are measured and modeled by computer. Students researched the literature and talked with scientists about the ecology, evolution, and behavior of these nocturnal fishes from South America and Africa. The class also developed and refined their own experimental protocols for observing the behavior of the fish, monitored the changes in the EOD in response to social interactions and the presence of predators, and utilized computer software to model and analyze their data.

       We presented some of our findings at the Society for Neuroscience convention in 1996.