Roverud R C
Department of Biology, University of California, Riverside 92521.
J Comp Physiol A. 1995 Jan;176(1):1-9. doi: 10.1007/BF00197747.
A stereotyped approach phase vocalization response of Noctilio albiventris to artificial echoes simulating a virtual approaching object was used to assess the ability of the bat to analyze and extract distance information from the artificial echoes. The performance of the bats depended on the temporal pattern of frequency change of the continuously sweeping frequency modulated (FM) component of the signals. When the bats were presented with a CF/FM signal containing a time-reversed upward FM sweep, they responded with approach phase behavior at a performance level that was significantly below that seen with a CF/FM signal containing a naturally structured downward FM sweep. When the FM sweep was divided into a series of brief pure tone steps, the extent to which the bats showed a difference in their capability to process upward versus downward FM sweeps depended on the difference in frequency between the pure tone steps. The bats effectively processed downward but not upward FM sweeps when the difference in frequency between pure tone frequency elements of the FM sweeps was from about 100-200 Hz, but they effectually processed both downward and upward FM sweeps when the tonal elements composing the FM sweeps were separated by more than about 200 Hz. This suggests that the ability of the bats to effectively process downward but not upward FM sweeps is based on local interactions between adjacent frequency elements of the complex sounds.
白线蝠（Noctilio albiventris）对模拟虚拟接近物体的人工回声的刻板接近阶段发声反应，被用于评估蝙蝠从人工回声中分析和提取距离信息的能力。蝙蝠的表现取决于信号连续扫频调频（FM）成分频率变化的时间模式。当给蝙蝠呈现一个包含时间反转向上调频扫频的CF/FM信号时，它们以接近阶段行为做出反应，其表现水平显著低于呈现包含自然结构向下调频扫频的CF/FM信号时的表现。当调频扫频被分成一系列简短的纯音步时，蝙蝠在处理向上和向下调频扫频能力上表现出差异的程度，取决于纯音步之间的频率差异。当调频扫频的纯音频率元素之间的频率差异约为100 - 200赫兹时，蝙蝠能有效地处理向下但不能处理向上的调频扫频，但当构成调频扫频的音调元素相隔超过约200赫兹时，它们能有效地处理向下和向上的调频扫频。这表明蝙蝠有效处理向下而非向上调频扫频的能力，是基于复杂声音相邻频率元素之间的局部相互作用。
