To understand how sensory inputs can guide behavior, it is important to identify how the structure of sensory signals, the patterns of brain activity that encode these signals, and the abilities of animals to perceive them are related. We still do not understand the general principles that link specific neural response properties with the structure of behaviorally relevant signals. This project will address this question by comparing how the brain encodes communication signals several closely related species of electric fish that display key differences in their signals. The project will use neurophysiological experiments, behavioral assays, and signal analysis to ask how brain mechanisms are optimized to species-specific signal properties and how these neural mechanisms influence the ability of the animals to perceive signals. The project will test the hypothesis that the structure of communication signals and the patterns of neural responses are efficiently matched across species to enable to detect and/or the discriminate conspecific signals. The model system, the communication signals of weakly electric fishes, is an ideal platform to link evolutionary, neurophysiological, and computational approaches to understanding the neural basis of behavior. Furthermore, electric fishes' use of a "sixth sense" to detect their world and communicate is a fascinating phenomenon that can engage public interest in animal diversity and neurobiology. The project will train high school, undergraduate, and graduate students. The researchers will also work with K-12 teachers to develop lesson plans that are linked to the project?s research and that are aligned with the learning goals of the AP Biology curriculum.
Communication signals often evolve with peripheral sensory filters to optimize species-specific signal capture. Much less is known, however, about how central sensory circuits evolve to efficiently extract and analyze complex features of conspecific signals. This project will comparatively study the communication signals and sensory systems of weakly electric fish to investigate relationships between signal structure, neural mechanisms of sensory processing, and perceptual tasks. The central hypothesis is that sensory coding and signal structure co-evolve in response to perceptual demands to permit efficient detection and discrimination of conspecific signals. The project will first analyze how cross-species variation in the structure of two communication signals that impinge on the same sensory channel influences the conspicuousness of signals. The project will then use in vivo electrophysiology to compare how the coding strategies of central sensory neurons are related to the structure of signals across species. Finally, behavioral tests will quantify how signal structure and sensory coding strategies influence the abilities of the fish to detect and discriminate signals. The project thus explicitly links signal diversity, sensory systems, and behavior. This project has strong potential to open a new direction in studying the mechanisms and evolution of communication systems by revealing how complex features of species-specific signals are co-adapted with neural coding strategies and the sensory tasks they accomplish. The CoPIs will take advantage of the interdisciplininary approaches of the project and the charismatic and engaging nature of the animal model to provide outreach and educational opportunities from the K-12 to advanced graduate levels.
