V-110
Sensory and Motor Systems
Role of Medial Olivocochlear Activity in the Maturation of Type II Cochlear Afferent Synapses
Eliana Sánchez1,2, Camila Catalano Di Meo1,3, Jimena A. Ballestero1, Amanda M. Lauer4, Ana B. Elgoyhen1, Radha Kalluri5, María E. Gómez-Casati1
1. Instituto de Farmacología, Facultad de Medicina, Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, CABA, Argentina.
2. Escuela de Ciencia y Tecnología, Universidad Nacional de San Martín, Buenos Aires, Argentina.
3. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, Dr. Héctor N. Torres, Consejo Nacional de Investigaciones Científicas y Técnicas, CABA, Argentina.
4. Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine; Baltimore, Maryland, United States.
5. Caruso Department of Otolaryngology-Head and Neck Surgery, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States.
Presenting Author:
Elysanchezzp@gmail.com
In the organ of Corti, inner hair cells (IHCs) transduce auditory signals, whereas outer hair cells (OHCs) amplify sound-induced vibrations. Cochlear afferent innervation includes type I neurons, which contact IHCs and form most of the auditory nerve, and type II neurons, which contact OHCs and whose function remains unclear. The cochlea also receives descending input from the brainstem through the medial olivocochlear (MOC) system, which targets OHCs, and the lateral olivocochlear (LOC) system, which contacts type I afferent terminals. During early development, MOC fibers transiently contact IHCs and modulate their spontaneous activity, thereby influencing the maturation of the auditory system. Previous work from our laboratory has shown that the level of efferent activity affects the developmental time course of auditory function and cochlear synaptic organization. In this study, we investigate how efferent activity influences the development of type II afferent synapses onto OHCs. Using immunofluorescence, we will examine the development of type II afferent synapses from postnatal day 6 to 75 in wild-type mice and in genetically modified mouse lines that either lack (α9 KO) or exhibit enhanced (α9 KI) MOC efferent activity.
