Biophysics Department, Donders Center for Neuroscience, Radboud University, Heyendaalseweg 135, 6525, AJ, Nijmegen, The Netherlands.
Sci Rep. 2018 Dec 18;8(1):17933. doi: 10.1038/s41598-018-36422-z.
How the human auditory system learns to map complex pinna-induced spectral-shape cues onto veridical estimates of sound-source elevation in the median plane is still unclear. Earlier studies demonstrated considerable sound-localisation plasticity after applying pinna moulds, and to altered vision. Several factors may contribute to auditory spatial learning, like visual or motor feedback, or updated priors. We here induced perceptual learning for sounds with degraded spectral content, having weak, but consistent, elevation-dependent cues, as demonstrated by low-gain stimulus-response relations. During training, we provided visual feedback for only six targets in the midsagittal plane, to which listeners gradually improved their response accuracy. Interestingly, listeners' performance also improved without visual feedback, albeit less strongly. Post-training results showed generalised improved response behaviour, also to non-trained locations and acoustic spectra, presented throughout the two-dimensional frontal hemifield. We argue that the auditory system learns to reweigh contributions from low-informative spectral bands to update its prior elevation estimates, and explain our results with a neuro-computational model.
人类听觉系统如何将复杂的耳廓诱发的频谱形状线索映射到中平面声源方位的真实估计值仍然不清楚。早期的研究表明，在应用耳廓模具和改变视觉后，声音定位具有相当大的可塑性。几个因素可能有助于听觉空间学习，例如视觉或运动反馈，或更新的先验知识。在这里，我们对具有低增益刺激-反应关系的频谱内容较差、具有较弱但一致的依赖于高度的线索的声音进行了知觉学习。在训练过程中，我们只为中矢状面的六个目标提供视觉反馈，听众逐渐提高了他们的反应准确性。有趣的是，即使没有视觉反馈，听众的表现也会有所提高，只是程度较低。训练后的结果显示，反应行为也得到了普遍改善，即使是非训练的位置和声音频谱，也在二维前半球面呈现。我们认为，听觉系统学会重新权衡来自低信息量频谱带的贡献，以更新其先验高度估计，并使用神经计算模型解释我们的结果。
