Detection of interaural time differences in the alligator.
Detection of interaural time differences in the alligator.
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DOI：
10.1523/jneurosci.6154-08.2009
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发表时间：
2009-06-24
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影响因子：
--
通讯作者：
Simon JZ
中科院分区：
文献类型：
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作者：
Carr CE;Soares D;Smolders J;Simon JZ
鸟类和哺乳动物的听觉系统使用每只耳朵的计时信息来检测耳间时间差(ITD)。为了确定鸟类对ITD敏感的Jeffress型算法是否是进化上稳定的策略，我们记录了鳄鱼的听觉核团，鳄鱼是鸟类的姐妹群。在鳄鱼中，一阶大细胞核(NM)中精确计时的尖峰信号编码了声音的计时，而NM神经元投射到板状核(NL)中的神经元，检测耳间时间差。来自NL神经元的活体记录显示，同侧和对侧输入的锁相峰电位的到达时间不同。当这种差异被最好的ITD抵消时，神经元的反应最大。因此，NL神经元充当符合探测器。一个带有鳄鱼参数的详细的NL生物模型可以识别高达1 kHz的ITD。然而，NL代表的最佳ITD的范围比鸟类大得多，从0到1000μS对侧，中位数为450μS。因此，鳄鱼和鸟类使用类似的算法来检测ITD，尽管鳄鱼的头更大。
The auditory systems of birds and mammals use timing information from each ear to detect interaural time difference (ITD). To determine whether the Jeffress-type algorithms that underlie sensitivity to ITD in birds are an evolutionarily stable strategy, we recorded from the auditory nuclei of crocodilians, who are the sister group to the birds. In alligators, precisely timed spikes in the first-order nucleus magnocellularis (NM) encode the timing of sounds, and NM neurons project to neurons in the nucleus laminaris (NL) that detect interaural time differences. In vivo recordings from NL neurons show that the arrival time of phase-locked spikes differs between the ipsilateral and contralateral inputs. When this disparity is nullified by their best ITD, the neurons respond maximally. Thus NL neurons act as coincidence detectors. A biologically detailed model of NL with alligator parameters discriminated ITDs up to 1 kHz. The range of best ITDs represented in NL was much larger than in birds, however, and extended from 0 to 1000 μs contralateral, with a median ITD of 450 μs. Thus, crocodilians and birds employ similar algorithms for ITD detection, although crocodilians have larger heads.