Toward model-guided electrophysiology-Encoding of chirps in the electrosensory periphery of Apteronotus leptorhynchus

Models formalize our understanding of a system and generate hypotheses that can be tested experimentally. In this study, we use a previously developed model of p-type electroreceptor afferents to support electrophysiological observations regarding the encoding of chirps in the electrosensory periphery of the weakly electric fish Apteronotus leptorhynchus. These animals employ their self-generated quasi-sinusoidal electric fields to navigate, find prey, and communicate. Electrocommunication happens in an electrosensory context that is defined by the superposition of the electric fields of the interacting animals. Within this context, chirps-brief excursions of the electric organ discharge frequency-interrupt the periodic interference pattern and are encoded in the responses of the electroreceptor afferents. Behavioral observations highlighted the immediate importance of chirps happening in contexts that were believed to be far outside the electroreceptor tuning, i.e., not encoded at all. Combining experiments with modeling, we show that chirps are nevertheless encoded under these conditions, identify how the encoding works in such contexts, and provide a deeper understanding of chirp encoding in the electrosensory periphery.