Graduation Year
2020
Document Type
Thesis
Degree
M.S.B.E.
Degree Name
MS in Biomedical Engineering (M.S.B.E.)
Degree Granting Department
Biomedical Engineering
Major Professor
George Spirou, Ph.D.
Committee Member
Paul Manis, Ph.D.
Committee Member
Joseph Walton, Ph.D.
Keywords
auditory processing, electron microscopy, neural circuits, sound localization, three-dimensional modeling
Abstract
Globular bushy cells (GBCs) of the cochlear nucleus are specialized neurons that encode the temporal features of sound. Multiple auditory nerve inputs are known to synapse onto a single GBC, but the exact number and sizes of these inputs have not been systematically investigated in adult mice. To gain a high-resolution and unbiased look at the auditory inputs contacting GBCs, our lab utilized Serial Block-Face Scanning Electron Microscopy. Specifically, 21 GBCs and all their large inputs were reconstructed at nanometer resolution. To produce the most precise results, we applied careful attention to the reconstruction and implemented cutting-edge meshing algorithms. We found that a range of 5 – 12 large auditory nerve terminals converge onto each GBC, which is higher than previously reported electrophysiological estimates. Interestingly, some GBCs were found to have a single large, dominant input, whereas others did not. Thus, we conclude that there are two models of GBC innervation, i.e., a mixed model (1 or 2 suprathreshold inputs and multiple subthreshold) and a coincidence detection model (all subthreshold inputs). The detailed reconstructions were then combined with a GBC computational model which confirmed the presence of two innervation models. We also present novel discoveries about the structure of GBCs that could only be seen in volume electron microscopy.
Scholar Commons Citation
Kersting, Matthew, "Convergence of Auditory Nerve Fibers onto Globular Bushy Cells" (2020). USF Tampa Graduate Theses and Dissertations.
https://digitalcommons.usf.edu/etd/9543
