Semester
Summer
Date of Graduation
2025
Document Type
Thesis
Degree Type
MS
College
Eberly College of Arts and Sciences
Department
Biology
Committee Chair
Gary Marsat
Committee Co-Chair
Andrew Dacks
Committee Member
Sarah Farris
Abstract
Animals have evolved sensory systems to help decipher important environmental signals that are vital for their survival. Feedback pathways are necessary to allow these signals to stand out in a noisy background, enabling the animal to focus on them more effectively. The electrosensory system of Apteronotus leptorhynchus allows the fish to sense the modulations caused by other conspecifics to allow for proper responses during social interactions. Electroreceptors detect these EODs, and afferent nerves project these signals to the ELL, where electrosensory information is projected to other parts of the brain. Cerebellar feedback to the ELL allows the suppression of lower frequency stimuli. However, little has been studied about the role of feedback in the spatial decoding of realistic, conspecific signals. This research was conducted to investigate the impact of feedback on the spatial processing of conspecific stimuli. We hypothesize that feedback enhances spatial coding by implementing background suppression and thereby enhancing spatial contrast. To test this hypothesis, a fish-pole was used to emit realistic stimuli to a receiver fish from three different positions, and the responses of pyramidal cells in the ELL were recorded. We found that cancellation occurs significantly with the gain of the beat and envelope while keeping the population's firing rate unaffected. Responses of the pyramidal cells were analyzed using a weighted Euclidean distance model, and we found that the overall efficiency of spatial discrimination increased when cancellation was present. Finally, the amount of cancellation and the efficiency of spatial discrimination is dependent on the history of the previous cycle of the beat. Feedback is shown to significantly improve spatial discrimination by suppressing background responses and thereby enhancing the spatial processing of communication signals.
Recommended Citation
Miller, Dakota Ray, "The effect of cerebellar feedback on the spatial processing of conspecific signals in the electrosensory system" (2025). Graduate Theses, Dissertations, and Problem Reports. 13005.
https://researchrepository.wvu.edu/etd/13005