Matthew L. Mendoza and G. Troy Smith

1. Conclusions Weakly Electric Fish Acknowledgements • Common name: brown ghost knifefish • Emit an electric organ discharge (EOD) from specialized organ in tail • EOD frequency (EODf) is the measurement of how often the EOD is emitted per second • Surgical removal of brain • Constant perfusion of Artificial Cerebrospinal Fluid (ACSF) • ACSF was saturated with 95% Oxygen and 5% Carbon Dioxide • Measured action potentials from PMN 1. The PMN in the whole-brain preparation remains viable after surgical removal. In fact, the firing rate of the PMN is strongly correlated to the fishes natural behavior. Males have a higher EODf than females 2. Upon chemical stimulation the whole-brain preparation produced a fictive chirp that is similar in structure to the fish’s natural communication signal. The x-axis is sex and the y-axis is EOD frequency measured in Hz. We verified that our fish show a consistent sexual dimorphism in their EODf. EOD and Communication Use of a Novel Whole-brain In Vitro Preparation to Study Electric Communication in Apteronotus leptorhynchus • EODf: continuously emitted information-rich badge • Chirps: brief modulation in EODf, used for motivational behaviors • Both communication signals are sexually dimorphic n=16 n=4 p<0.001 * Future Directions Firing frequencies of PMN in whole-brain prep correlates to EODf The x-axis is the fish’s natural behavior (EODf) and the y-axis is the isolated whole-brain prep. The isolated whole-brain prep fired at rates similar to the fish’s natural behavior. Neural Circuitry P<0.001* r2=0.835 Experiment 2: Production of Fictive Chirps • Test the role of neuromodulators during the modulation of EODf Matthew L. Mendoza and G. Troy Smith McNair Scholars Program, Department of Biological Sciences, University of North Texas, Denton, Texas Center for Intergrative Study Animal Behavior, Department of Biology, Program in Neuroscience, Indiana, University, Bloomington, Indiana References Cited Whole-brain Prep 1. Dye, J. 1988. An in vitro physiological preparation of a vertebrate communicatory behavior: chirping in the weakly electric fish, Apteronous. Journal of Comparative Phyisology. Vol 163. pp 445-458. 2. Heiligenberg W, Metzner W. Wong C.J.H. 1996. Motor Control of the Jamming Avoidance Response of Apteronotus leptorhynchus: Evolutionary Changes of a Behavior and its Neuronal Substrates. Journal of Comparative Physiology. Vol 179. Pp. 655-674. 3. Kolodziejski, Johanna A, Nelson S. Brain, Smith G. Troy. 2005. Sex and Species Differences in Neuromodualatory Inout to a premotor Nucleus: A comparative study of Substance P and Communication Behavior in Weakly Electric Fis. Journal Of Neurobiology. Vol 62. Pp. 299-315. 4. Smith G. Troy. 2013. Evolution and Hormonal Regulation of Sex Differences in the Electrocommunication of Ghost Knife Fish (Apteronotidae). Behavior, Neurobiology, and Neuroendocrinology. Hormones, Brain, and Behavior. 5. Zakon H H and Smith G T, 2009 Weakly Electric Fish: Behavior, Neurobiology, and Neuroendocrinology. Hormones, Brain and Behavior, 2nd edition, Vol 1. 2009. pp. 611-638. Experiment 1: Production of a Fictive EOD • Chemical stimulation • 1)Iontophoresis • 2)Pressure application • Electrical stimulation • Tracked electrode with fluorescent marker • Most stimulation sites missed PPn-C Research Questions 1. Does the natural behavior of the fish (EODf) correlate to the reduced system’s action potential firing rate in the PMN? Before stimulation CISAB Linda Summers Ali Ossip-Klein Dr. Hurley and REU Selection Committee IU Department of Biology The Smith’s Lab UNT McNair Scholars Program Dr. Jannon Fuchs 2. Is this reduced system capable of producing a fictive chirp that is similar to the fish’s natural chirping behavior? After stimulation After stimulation the whole-brain produced a fictive chirp. The x-axes are time (sec) and the y-axes are measurements of amplitude (mV) and frequency (Hz). After stimulation there were fluctuations in frequency and amplitude. As the frequency decreased the amplitude increased.