remains unknown. Studies examining the temporal bone of patients affected by MD have revealed a condition called endolymphatic hydrops, an expansion of the scala media suggesting a disruption in the balance of fluids within the inner ear. Endolymph, a crucial fluid within the membranous labyrinth of the inner ear, plays a pivotal role in maintaining both hearing and balance. Despite its significance, our understanding of how this fluid is regulated remains limited. Considering the importance of fluid homeostasis in the inner ear, the goal of our research is to understand the formation of endolymphatic hydrops and the consequences on neuronal dysfunction. In this research, we will investigate inner ear dysfunction in an animal model of endolymphatic hydrops. Aim 1: We will correlate hearing and balance thresholds with the ionic and protein composition of endolymph and perilymph. Aim 2: We will test if there is degradation of the blood endolymph barrier during development of endolymphatic hydrops. Aim 3: We will conduct transcriptomic analysis on the hydropic neurons to better understand the cause of neuronal dysfunction during the development of endolymphatic hydrops. These studies are essential for comprehending potential mechanisms underlying disruptions in inner ear homeostasis and the development of conditions like MD. This understanding will be essential in developing targeted therapies for MD and related conditions.