NEURAL TUNING CHARACTERISTICS OF AUDITORY PRIMARY AFFERENTS IN THE CHICKEN-EMBRYO
NEURAL TUNING CHARACTERISTICS OF AUDITORY PRIMARY AFFERENTS IN THE CHICKEN-EMBRYO
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DOI：
10.1016/0378-5955(94)00172-m
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发表时间：
1995-02-01
期刊：
影响因子：
2.8
通讯作者：
JONES, TA
中科院分区：
文献类型：
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作者：
JONES, SM;JONES, TA
在孵育19天（E19）时，记录鸡胚（Gallus arcticus）耳蜗神经节的初级传入活动。通过鼓阶隐窝进入神经节，并用玻璃微量移液管刺穿。频率调谐曲线使用计算机阈值跟踪程序获得。对调谐曲线进行了评估，以确定特征频率（CF）、CF阈值、低频和高频侧翼的斜率以及尖端锐度（Q（10 dB））。大多数调谐曲线显示出老年鸟类的典型“V”形，平均而言，基于CF阈值（59.6 +/- 20.3 dBSPL）和尖端锐度（Q（10 dB）= 5.2 +/- 3）的平均值，显示相对成熟。低（61.9 +/- 37 dB/倍频程）和高（64.6 +/- 33 dB/倍频程）频率侧翼的平均斜率虽然相当，但略低于21日龄鸡报告的斜率。大约14%的调谐曲线显示出不寻常的“锯齿”图案。CF范围为188至1623 Hz。最高CF远低于孵化后鸟类报告的CF。此外，更宽范围的Q（10 dB）值（1.2至16.9）可能与胚胎调谐曲线的更大变异性有关。总的来说，这些数据表明，在E19胚胎中存在令人印象深刻的功能成熟。不成熟的最显著标志是高频率的有限表达。有人认为，有限的高CF部分可能是由于中耳传递功能的发育和/或耳蜗基底的功能不成熟。
Primary afferent activity was recorded from the cochlear ganglion in chicken embryos (Gallus domesticus) at 19 days of incubation (E19). The ganglion was accessed via the recessus scala tympani and impaled with glass micropipettes. Frequency tuning curves were obtained using a computerized threshold tracking procedure. Tuning curves were evaluated to determine characteristic frequencies (CFs), CF thresholds, slopes of low and high frequency flanks, and tip sharpness (Q(10dB)).The majority of tuning curves exhibited the typical 'V' shape described for older birds and, on average, appeared relatively mature based on mean values for CF thresholds (59.6 +/- 20.3 dBSPL) and tip sharpness (Q(10dB) = 5.2 +/- 3). The mean slopes of low (61.9 +/- 37 dB/octave) and high (64.6 +/- 33 dB/octave) frequency flanks although comparable were somewhat less than those reported for 21-day-old chickens. Approximately 14% of the tuning curves displayed an unusual 'saw-tooth' pattern. CFs ranged from 188 to 1623 Hz. The highest CF was well below those reported for post-hatch birds. In addition, a broader range of Q(10dB) values (1.2 to 16.9) may relate to a greater variability in embryonic tuning curves. Overall, these data suggest that an impressive functional maturity exists in the embryo at E19. The most significant sign of immaturity was the limited expression of high frequencies. it is argued that the limited high CF in part may be due to the developing middle ear transfer function and/or to a functionally immature cochlear base.