A Potential Neural Substrate for Processing Functional Classes of Complex Acoustic Signals
A Potential Neural Substrate for Processing Functional Classes of Complex Acoustic Signals
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DOI：
10.1371/journal.pone.0002203
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发表时间：
2008-05-21
期刊：
影响因子：
3.7
通讯作者：
Hausberger, Martine
中科院分区：
文献类型：
--
作者：
George, Isabelle;Cousillas, Hugo;Hausberger, Martine
分类对所有认知过程都至关重要，但识别分类过程背后的神经基质是一个真正的挑战。在已被证明具有分类能力的动物中，鸣禽尤其令人感兴趣，因为它们为研究人员提供了清晰的例子，说明声音信号的类别允许不同程度的识别，而且它们拥有一种专门的大脑结构系统，这种系统只存在于学会唱歌的鸟类中：鸣叫系统。此外，鸟类的大脑核类似于哺乳动物的次级听觉皮层（尾内侧nidopallium，或NCM），最近被认为是鸟类鸣叫感觉表征的合理位置，并且似乎是一个定位良好的鸣叫分类的大脑区域。因此，我们测试了在这个非主要的联想区域对具有不同功能和社会价值的明确和不同类别的歌曲的反应，以及这些反应与歌曲功能方面之间可能的对应关系，在高度社会性的鸣禽物种中：欧洲椋鸟。我们的研究结果清楚地显示了不同的神经元对不同种类的歌曲的反应，无论是在神经元的数量上，还是在这些神经元的反应幅度上。最重要的是，这些不同的反应对应于歌曲的功能类别，从非特异性到物种特异性以及从物种特异性到个体特异性的声音的激活增加。因此，这些数据表明，对自然交流信号进行分类的潜在神经基质，以及对同一物种成员的个体声音识别。鉴于鸟鸣和语言之间存在许多相似之处，这些结果可能有助于更好地理解语言的神经基础。
Categorization is essential to all cognitive processes, but identifying the neural substrates underlying categorization processes is a real challenge. Among animals that have been shown to be able of categorization, songbirds are particularly interesting because they provide researchers with clear examples of categories of acoustic signals allowing different levels of recognition, and they possess a system of specialized brain structures found only in birds that learn to sing: the song system. Moreover, an avian brain nucleus that is analogous to the mammalian secondary auditory cortex ( the caudo-medial nidopallium, or NCM) has recently emerged as a plausible site for sensory representation of birdsong, and appears as a well positioned brain region for categorization of songs. Hence, we tested responses in this non-primary, associative area to clear and distinct classes of songs with different functions and social values, and for a possible correspondence between these responses and the functional aspects of songs, in a highly social songbird species: the European starling. Our results clearly show differential neuronal responses to the ethologically defined classes of songs, both in the number of neurons responding, and in the response magnitude of these neurons. Most importantly, these differential responses corresponded to the functional classes of songs, with increasing activation from non-specific to species-specific and from species-specific to individual-specific sounds. These data therefore suggest a potential neural substrate for sorting natural communication signals into categories, and for individual vocal recognition of same-species members. Given the many parallels that exist between birdsong and speech, these results may contribute to a better understanding of the neural bases of speech.