Salminen Nelli H, Tiitinen Hannu, May Patrick J C
Helsinki University of Technology, Helsinki, Finland.
Cogn Affect Behav Neurosci. 2009 Sep;9(3):304-13. doi: 10.3758/CABN.9.3.304.
Our native language has a lifelong effect on how we perceive speech sounds. Behaviorally, this is manifested as categorical perception, but the neural mechanisms underlying this phenomenon are still unknown. Here, we constructed a computational model of categorical perception, following principles consistent with infant speech learning. A self-organizing network was exposed to a statistical distribution of speech input presented as neural activity patterns of the auditory periphery, resembling the way sound arrives to the human brain. In the resulting neural map, categorical perception emerges from most single neurons of the model being maximally activated by prototypical speech sounds, while the largest variability in activity is produced at category boundaries. Consequently, regions in the vicinity of prototypes become perceptually compressed, and regions at category boundaries become expanded. Thus, the present study offers a unifying framework for explaining the neural basis of the warping of perceptual space associated with categorical perception.
我们的母语对我们感知语音的方式有着终身影响。在行为上，这表现为范畴知觉，但这种现象背后的神经机制仍然未知。在这里，我们构建了一个范畴知觉的计算模型，遵循与婴儿语音学习一致的原则。一个自组织网络暴露于作为听觉外周神经活动模式呈现的语音输入的统计分布中，类似于声音到达人类大脑的方式。在由此产生的神经图谱中，范畴知觉源于模型中的大多数单个神经元被典型语音最大程度地激活，而活动的最大变异性则在类别边界处产生。因此，原型附近的区域在感知上被压缩，而类别边界处的区域则被扩展。因此，本研究为解释与范畴知觉相关的感知空间扭曲的神经基础提供了一个统一的框架。
