Meeting Abstract

P3.24  Saturday, Jan. 5  Variation in orderliness of the sensory array of the mammalian inner ear SWIDERSKI, D.L.*; RAPHAEL, Y.; U. Michigan, Ann Arbor; U. Michigan, Ann Arbor dlswider@umich.edu

The organ of Corti, the sensory epithelium of the mammalian inner ear is composed of a mosaic of sensory hair cells and non-sensory supporting cells. The orderliness of this array, the consistent spacing, alignment and orientation the cells, distinguishes the organ of Corti from the auditory epithelium of other tetrapods and may contribute to the enhanced auditory capabilities of mammals. Informal, qualitative assessments of normal, healthy guinea pigs and mice suggest that cell spacing and alignment tend to be more consistent than stereocilia bundle orientation throughout the organ of Corti. These features are less consistent in the outermost row than in any inner row, and consistency in all rows declines sharply near the apex of the organ. In addition, there appears to be less order in animals exposed to acoustic or ototoxic insult, and in strains of mice carrying mutations in genes coding different structural proteins of the stereocilia. Thus quantitative measures of orderliness could provide a means of assessing severity of trauma or disruption of genetic and developmental integration; and restoration of orderliness could be used as a measure of the efficacy of treatment. In this study, we quantify distributions of several features of organ of Corti organization, including the distance and direction between neighboring hair cells, and the shape and orientation of the stereociliary bundle and compare distribution between hair cell rows and between cochlear turns.