鸣鸟会学习发音，即它们会学习去模仿“老师”的叫声。在一个嘈杂的群落中，这意味着鸣鸟个体需要区分自己发出的声音和其他鸟儿发出的声音，从而使其能够准确匹配学到的叫声模板。为此，人们长期假设，同人类一样，鸣鸟也拥有一个能探测声音错误的大脑机制。现在，George Keller 和Richard Hahnlose在斑胸草雀的听觉前脑中发现了专门对叫声或回放声音的扰动做出反应的神经元，说明在其前脑的听觉区域存在一个纠正错误的计算功能。这一发现证实，很早之前就建立起来的一个理论概念——“内部模型理论”是声音模仿学习的基础。（生物谷Bioon.com）
生物谷推荐原始出处：
Nature 457, 187-190 (8 January 2009) | doi:10.1038/nature07467
Neural processing of auditory feedback during vocal practice in a songbird
Georg B. Keller1 & Richard H. R. Hahnloser1
1 Institute of Neuroinformatics, University of Zurich/ETH Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
Songbirds are capable of vocal learning and communication1, 2 and are ideally suited to the study of neural mechanisms of complex sensory and motor processing. Vocal communication in a noisy bird colony and vocal learning of a specific song template both require the ability to monitor auditory feedback3, 4 to distinguish self-generated vocalizations from external sounds and to identify mismatches between the developing song and a memorized template acquired from a tutor5. However, neurons that respond to auditory feedback from vocal output have not been found in song-control areas despite intensive searching6, 7, 8. Here we investigate feedback processing outside the traditional song system, in single auditory forebrain neurons of juvenile zebra finches that were in a late developmental stage of song learning. Overall, we found similarity of spike responses during singing and during playback of the bird's own song, with song responses commonly leading by a few milliseconds. However, brief time-locked acoustic perturbations of auditory feedback revealed complex sensitivity that could not be predicted from passive playback responses. Some neurons that responded to playback perturbations did not respond to song perturbations, which is reminiscent of sensory-motor mirror neurons8, 9. By contrast, some neurons were highly feedback sensitive in that they responded vigorously to song perturbations, but not to unperturbed songs or perturbed playback. These findings suggest that a computational function of forebrain auditory areas may be to detect errors between actual feedback and mirrored feedback deriving from an internal model of the bird's own song or that of its tutor. Such feedback-sensitive spikes could constitute the key signals that trigger adaptive motor responses to song disruptions10, 11 or reinforce exploratory motor gestures for vocal learning12.
