Cody A R
Department of Physiology and Pharmacology, University of Queensland, Australia.
Hear Res. 1992 Oct;62(2):166-72. doi: 10.1016/0378-5955(92)90182-m.
The spatial contribution of mechanically active hair cells to tuning and sensitivity at a single point in the mammalian cochlea has been investigated in the basal turn of the guinea pig cochlea. Following the destruction of outer hair cells with acoustic overstimulation it was possible to record apparently normal tuning and sensitivity from spiral ganglion neurones innervating inner hair cells located on the apical edges of substantial lesions. The distance between the recording site, where neurones showed normal sensitivity, and areas of the cochlea showing 60-100% of the outer hair cells either damaged or missing varied between 0.2 and 1.3 mm which incorporates approximately 70 to 450 outer hair cells. In one animal neurones that demonstrated normal sensitivity were recorded within 0.2 mm of a lesion where 67% of the outer hair cells were either missing or showed severe damage to their stereocilia and within 0.5 mm of areas of the organ of Corti showing damage to 97% of the outer hair cells. This distance includes approximately 50 inner hair cells or 180 outer hair cells. The location of these neurones, whose sharp tuning presumably mirrors basilar membrane mechanics, suggests that a substantial proportion of point tuning in the cochlea may be derived over a distance of less than 0.5 mm and involve fewer than 200 active outer hair cells.
在豚鼠耳蜗的基部转弯处，研究了机械活动毛细胞对哺乳动物耳蜗中某一点的调谐和灵敏度的空间贡献。在用声学过度刺激破坏外毛细胞后，有可能从支配位于大量病变顶端边缘的内毛细胞的螺旋神经节神经元记录到明显正常的调谐和灵敏度。神经元显示正常灵敏度的记录部位与耳蜗中显示60 - 100%的外毛细胞受损或缺失的区域之间的距离在0.2至1.3毫米之间，这包含了大约70至450个外毛细胞。在一只动物中，在一个病变0.2毫米范围内记录到了显示正常灵敏度的神经元，该病变处67%的外毛细胞缺失或其静纤毛显示出严重损伤，并且在柯蒂氏器显示97%的外毛细胞受损区域的0.5毫米范围内也记录到了此类神经元。这个距离包括大约50个内毛细胞或180个外毛细胞。这些神经元的位置，其尖锐调谐大概反映了基底膜力学，表明耳蜗中相当一部分点调谐可能在小于0.5毫米的距离内产生，并且涉及少于200个活跃的外毛细胞。
