Individual Variability of the Medial Superior Olive in the Human Brainstem

Authors: Bryan Lukyanenko, Joan Baizer

SUNY Campus: SUNY Buffalo

Presentation Type: Oral

Location: UUW 324

Presentation #: 4

Timeslot: Session C 1:45-2:45 PM

Abstract: The superior olivary complex (SOC) in the brainstem plays a crucial role in sound localization. In non-human mammals, the SOC is composed of many distinct nuclei, including the lateral superior olive (LSO), the medial superior olive (MSO), and the medial nucleus of the trapezoid body (MNTB). However, in humans, only the MSO has been consistently identified. We previously found individual variability in the rostrocaudal extent of the MSO, leading us to ask whether the overall shape, area, and cell density of the MSO may also vary. This study investigates these questions. We studied 14 human brainstems from the Witelson Normal Brain Collection. We examined Nissl and immunostained transverse sections to identify the rostrocaudal extent of the MSOwhich ranged from 3.8 mm to 6.4 mm. We measured MSO areas in sections taken from the midpoints of their rostrocaudal extents and found differences in shape between the left and right sides. Using ImageJ, we calculated the cell density and found an inverse relationship between rostrocaudal extent of the MSO and cell density, although it did not reach statistical significance. Our research demonstrates variability in rostrocaudal extent, areas, cell density, and shape of the MSO. These findings provide a deeper understanding of the structural variability in the MSOwhich could be used for future advancements in individualized treatments of auditory disorders affecting sound localization.