Performance variability enables adaptive plasticity of 'crystallized' adult birdsong
Performance variability enables adaptive plasticity of 'crystallized' adult birdsong
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DOI：
10.1038/nature06390
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发表时间：
2007-12-20
期刊：
影响因子：
64.8
通讯作者：
Brainard, Michael S.
中科院分区：
文献类型：
--
作者：
Tumer, Evren C.;Brainard, Michael S.
即使在最熟练的技能中，显著的一次又一次的变化仍然存在。一种流行的观点是，这种变化只是神经系统无法控制的“噪音”，或者仍然低于行为相关性的阈值（1-3）。另一种假设是，这种变异使试错学习成为可能，在这种学习中，运动系统产生变异，并以不同的方式保留行为，从而产生更好的结果。在这里，我们测试了后一种可能性，成年孟加拉雀的歌声。成年鸟的鸣叫是一种复杂的、后天习得的运动技能，以一种高度刻板的方式从一种演唱到下一种（4,5）。然而，即使在稳定的、“结晶”的成人歌曲中，也存在细微的变化。我们使用一个计算机化的系统来监测目标歌曲元素音高的微小自然变化，并对这些变化的子集提供实时听觉干扰。鸟类以一种适应性的方式迅速改变它们发声的音调，以避免干扰。这些声音的变化被精确地限制在歌曲的目标特征上。因此，鸟类能够通过将声音行为的微小变化与不同的结果联系起来来有效地学习。这样的过程可以帮助维持稳定的、习得的歌声，尽管声音控制系统因衰老或受伤而发生变化。更一般地说，我们的研究结果表明，在良好的学习技能中，剩余的可变性并不完全是噪音，而是反映了有意义的运动探索，可以支持持续学习和性能优化。
Significant trial- by- trial variation persists even in the most practiced skills. One prevalent view is that such variation is simply 'noise' that the nervous system is unable to control or that remains below threshold for behavioural relevance(1-3). An alternative hypothesis is that such variation enables trial- and- error learning, in which the motor system generates variation and differentially retains behaviours that give rise to better outcomes. Here we test the latter possibility for adult bengalese finch song. Adult bird-song is a complex, learned motor skill that is produced in a highly stereotyped fashion from one rendition to the next(4,5). Nevertheless, there is subtle trial- by- trial variation even in stable, 'crystallized' adult song(6-8). We used a computerized system to monitor small natural variations in the pitch of targeted song elements and deliver real- time auditory disruption to a subset of those variations. Birds rapidly shifted the pitch of their vocalizations in an adaptive fashion to avoid disruption. These vocal changes were precisely restricted to the targeted features of song. Hence, birds were able to learn effectively by associating small variations in their vocal behaviour with differential outcomes. Such a process could help to maintain stable, learned song despite changes to the vocal control system arising from ageing or injury. More generally, our results suggest that residual variability in well learned skills is not entirely noise but rather reflects meaningful motor exploration that can support continuous learning and optimization of performance.