Makous J C, O'Neill W E
Hear Res. 1986;24(1):73-88. doi: 10.1016/0378-5955(86)90006-7.
To ascertain the directional characteristics of the auditory system in the mustached bat, Pteronotus parnellii, we measured the summated neural response at the lateral lemniscus (N4) in response to pure tones at 30, 60 and 90 kHz, frequencies that are typical of the harmonics of this species' biosonar signal. Stimuli were presented at various vertical and horizontal locations in the contralateral hemifield. Intensity-response functions were measured at different horizontal locations for the second harmonic, and showed no variation in shape with variations in azimuth. There was little difference in directionality measured from either threshold or amplitude of N4 potentials. Our results show that areas of maximum sensitivity (best areas) were significantly different for each of the harmonics (P less than 0.05). The centers of the best areas were: first harmonic (30 kHz), 39 degrees azimuth and -19 degrees elevation; second harmonic, 20 degrees azimuth and 0 degrees elevation; and third harmonic, 12 degrees azimuth and -11 degrees elevation. Thus, with increasing frequency best areas shifted toward the vertical midline. Directionality to first harmonic stimuli was broader than to either of the two higher harmonics.
为了确定髯蝠（Pteronotus parnellii）听觉系统的方向特性，我们测量了外侧丘系（N4）对30、60和90千赫兹纯音的总和神经反应，这些频率是该物种生物声纳信号谐波的典型频率。刺激在对侧半视野的不同垂直和水平位置呈现。测量了二次谐波在不同水平位置的强度-反应函数，结果显示其形状不会随方位变化而改变。从N4电位的阈值或幅度测量的方向性几乎没有差异。我们的结果表明，每个谐波的最大敏感区域（最佳区域）存在显著差异（P小于0.05）。最佳区域的中心分别为：一次谐波（30千赫兹），方位角39度，仰角-19度；二次谐波，方位角20度，仰角0度；三次谐波，方位角12度，仰角-11度。因此，随着频率增加，最佳区域向垂直中线移动。一次谐波刺激的方向性比两个更高谐波的都要宽。
