Analysis of Multisensory Integration in Weakly Electric Fish

Abstract

Animals routinely integrate multisensory information while controlling their movement. This is accomplished by integrating information from multiple sensory modalities within the CNS. To improve sensory performance, animals dynamically tune the contributions of each sensory modality. Our goal is to reveal how the weights associated with different sensory organs change in relation to the salience of the sensory information. We built experimental setups to separately identify the weights assigned to visual and electrosensory information by weakly electric fish, Eigenmannia virescens and Apteronotus albifrons, during their refuge tracking behavior. The key feature of our experimental setup is that visual and electrosensory cues can be controlled independently. We conducted many different experiments to analyze the relationship between sensory salience and sensory reweighting. We conducted a series of different experiments to analyze the relationship between sensory salience and sensory reweighting. First, we conducted experiments with Apteronotus albifrons under constant sensory salience levels to measure its sensory weights. We observed that this fish did not show tracking behavior in response to visual cues, thus, we concluded that this fish was not a good choice to study MSI. From that point on, we continued our experiments with Eigenmannia virescens that has better refuge tracking performance. We first conducted experiments under constant sensory salience conditions and observed that both cues were able to trigger tracking behavior. However, the response to the visual cue was slightly higher than the response to the electrosensory cue. Afterward, we conducted similar experiments under continuously changing visual sensory salience levels. We noticed that the fish reweighted associated sensory weights under different salience levels, and they were able to keep their overall tracking performance at the same point. The future direction is to investigate models that capture the dynamics of sensory reweighting in relation to sensory salience.