Postnatal Changes in the Afferent Innervation of Hair Cells in the Rodent Cochlea

成年哺乳动物耳蜗至少包含两种形态类型的螺旋神经节神经元。ⅰ型螺旋神经节细胞通过较粗的径向纤维与内毛细胞接触，ⅱ型螺旋神经节细胞通过较细的外螺旋纤维与外毛细胞接触。然而，在新生儿耳蜗中，螺旋神经节细胞似乎是一个均匀的群体，一些螺旋神经节细胞似乎与内毛细胞和外毛细胞接触。本研究将在豚鼠和仓鼠的单细胞水平上对外毛细胞螺旋神经节细胞的神经支配进行研究。本研究的总体目标是通过广泛研究ii型神经元的解剖发育，进一步了解ii型神经元在听力中的作用。这样一个系统的研究将有助于进一步解决成人神经支配模式如何产生。

The adult mammalian cochlea contains at least two morphological types of spiral ganglion neurons. Type-I spiral ganglion cells contact inner hair cells via thick radial fibers while type-II spiral ganglion cells contact outer hair cells via thinner outer spiral fibers. However, in newborn cochlea spiral ganglion cells appear as a homogeneous population, and some spiral ganglion cells appear to contact both inner and outer hair cells. This research on guinea pigs and hamsters will focus on the spiral ganglion cell innervation of outer hair cells at a single- cell level. The overall objective of this research is to gain additional insights into the role of type-II neurons in hearing by extensively studying their anatomical development. Such a systematic study will help to further resolve how adult innervation patterns arise.