Rapid jamming avoidance in biosonar.
Rapid jamming avoidance in biosonar.
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DOI：
10.1098/rspb.2006.0047
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发表时间：
2007-03-07
期刊：
影响因子：
--
通讯作者：
McCracken, Gary F
中科院分区：
文献类型：
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作者：
Gillam, Erin H;Ulanovsky, Nachum;McCracken, Gary F
蝙蝠和海豚的声纳系统在许多方面优于人造声纳和雷达系统，人们花了相当大的努力来理解这些能力背后的信号处理策略。决定声纳系统效率的一个主要特征是对噪声和干扰信号的敏感度。先前的研究表明，回声定位蝙蝠可能会调整它们的信号结构以避免干扰(‘干扰回避反应’；JAR)。然而，这些研究依赖于行为相关性，而不是对照实验。在这里，我们提供了蝙蝠体内JAR的第一个实验证据。我们给蝙蝠(Tadarida Brasiliens)提供了由六种频率中的一种记录的回声定位叫声组成的“回放刺激”。蝙蝠通过改变它们的叫声频率远离呈现的回放频率来展示一个罐子。当接近的蝙蝠受到回放刺激突然变化的挑战时，它们的反应是向上移动它们的叫声频率，远离回放。有趣的是，甚至连蝙蝠最初的叫声频率都低于播放频率，它们的频率也向上移动，跳过了播放频率。蝙蝠叫声中的这些光谱变化通常发生在不到200毫秒的时间内，这是在刺激切换后发出的第一次回声定位呼叫中--这表明快速避免干扰对蝙蝠来说很重要。
The sonar systems of bats and dolphins are in many ways superior to man-made sonar and radar systems, and considerable effort has been devoted to understanding the signal-processing strategies underlying these capabilities. A major feature determining the efficiency of sonar systems is the sensitivity to noise and jamming signals. Previous studies indicated that echolocating bats may adjust their signal structure to avoid jamming ('jamming avoidance response'; JAR). However, these studies relied on behavioural correlations and not controlled experiments. Here, we provide the first experimental evidence for JAR in bats. We presented bats (Tadarida brasiliensis) with 'playback stimuli' consisting of recorded echolocation calls at one of six frequencies. The bats exhibited a JAR by shifting their call frequency away from the presented playback frequency. When the approaching bats were challenged by an abrupt change in the playback stimulus, they responded by shifting their call frequencies upwards, away from the playback. Interestingly, even bats initially calling below the playback's frequency shifted their frequencies upwards, 'jumping' over the playback frequency. These spectral shifts in the bats' calls occurred often within less than 200 ms, in the first echolocation call emitted after the stimulus switch-suggesting that rapid jamming avoidance is important for the bat.