Smith D W, Brown J N, Moody D B, Stebbins W C, Nuttall A L
Hear Res. 1987;26(3):311-7. doi: 10.1016/0378-5955(87)90066-9.
Lesions of the hair cells in the cochlear apex were produced by a miniature cryoprobe and changes in behavioral auditory thresholds were measured. Monauralized adult chinchillas were behaviorally trained using operant procedures to produce pure-tone audiograms at frequencies from 63 Hz to 40 kHz. Following collection of baseline thresholds, the apical and middle turns of the experimental ear were visualized through a hole drilled in the bulla and a copper cryoprobe that had been cooled in liquid nitrogen was placed on the apical turn of the cochlea. Post-lesion threshold shifts from two subjects showed a flat loss of approximately 20 dB restricted to frequencies below either 710 Hz or 1 kHz; thresholds were normal at higher frequencies. The cytocochleograms, prepared from the ears following completion of threshold testing, show an almost complete loss of both inner and outer hair cells in the apical-most 20% of the cochlea with an abrupt transition region to areas of normal-looking hair cell populations. The relationship between the frequencies at which hearing was impaired and the location of missing hair cells along the basilar membrane is in agreement with the frequency-place map for the chinchilla of Eldredge et al. [(1981) J. Acoust. Soc. Am. 69, 1091-1095]. The magnitude of the loss, however, is less than might be expected based on comparison with threshold shifts produced by similar pathology in the basal turns.
用微型冷冻探头造成耳蜗顶部毛细胞损伤，并测量行为性听觉阈值的变化。使用操作性程序对成年单耳沙鼠进行行为训练，以生成63Hz至40kHz频率范围内的纯音听力图。在收集基线阈值后，通过在听泡上钻的孔观察实验耳的顶部和中部蜗旋，并将在液氮中冷却的铜冷冻探头置于耳蜗顶部蜗旋上。两名受试者损伤后的阈值变化显示，在710Hz或1kHz以下频率出现约20dB的平稳听力损失；较高频率的阈值正常。在阈值测试完成后从耳朵制备的细胞耳蜗图显示，在耳蜗最顶部20%区域内、外毛细胞几乎完全缺失，与外观正常的毛细胞群体区域有一个突然的过渡区。听力受损频率与基底膜上缺失毛细胞位置之间的关系与Eldredge等人[(1981)《美国声学学会杂志》69, 1091 - 1095]所绘制的沙鼠频率 - 位置图一致。然而，与基底蜗旋类似病变产生的阈值变化相比，损失程度小于预期。
