Kacelnik Oliver, Nodal Fernando R, Parsons Carl H, King Andrew J
Department of Physiology, Anatomy, and Genetics, University of Oxford, United Kingdom.
PLoS Biol. 2006 Apr;4(4):e71. doi: 10.1371/journal.pbio.0040071. Epub 2006 Mar 7.
Accurate auditory localization relies on neural computations based on spatial cues present in the sound waves at each ear. The values of these cues depend on the size, shape, and separation of the two ears and can therefore vary from one individual to another. As with other perceptual skills, the neural circuits involved in spatial hearing are shaped by experience during development and retain some capacity for plasticity in later life. However, the factors that enable and promote plasticity of auditory localization in the adult brain are unknown. Here we show that mature ferrets can rapidly relearn to localize sounds after having their spatial cues altered by reversibly occluding one ear, but only if they are trained to use these cues in a behaviorally relevant task, with greater and more rapid improvement occurring with more frequent training. We also found that auditory adaptation is possible in the absence of vision or error feedback. Finally, we show that this process involves a shift in sensitivity away from the abnormal auditory spatial cues to other cues that are less affected by the earplug. The mature auditory system is therefore capable of adapting to abnormal spatial information by reweighting different localization cues. These results suggest that training should facilitate acclimatization to hearing aids in the hearing impaired.
精确的听觉定位依赖于基于每只耳朵接收到的声波中存在的空间线索进行的神经计算。这些线索的值取决于两只耳朵的大小、形状和间距，因此因人而异。与其他感知技能一样，参与空间听觉的神经回路在发育过程中会受到经验的塑造，并在以后的生活中保持一定的可塑性。然而，在成人大脑中促成并促进听觉定位可塑性的因素尚不清楚。在此我们表明，成年雪貂在通过可逆地堵塞一只耳朵改变其空间线索后，能够快速重新学习声音定位，但前提是它们要在行为相关任务中接受使用这些线索的训练，训练越频繁，改善就越大且越快。我们还发现，在没有视觉或错误反馈的情况下听觉适应也是可能的。最后，我们表明这个过程涉及敏感性从异常的听觉空间线索转移到受耳塞影响较小的其他线索。因此，成熟的听觉系统能够通过重新权衡不同的定位线索来适应异常的空间信息。这些结果表明，训练应有助于听力受损者适应助听器。
