Neural entrainment to speech kinematics

Objectives
Speech processing entails a complex interplay between bottom-up entrainment to the quasi-rhythmic properties of speech acoustics and top-down modulation guiding attention in time and aiding selection of the most relevant input subspaces. Top-down signals are believed to originate mainly from motor regions, yet similar activities have been shown to tune attentional cycles also for simpler, non-speech stimuli. Here we examined whether neural signals encode detailed articulatory information, pointing to the involvement of a domain-specific mechanism during speech listening.
Materials
We measured electroencephalographic (EEG) data while participants listened to sentences for which articulatory kinematics of lips, jaws and tongue were also available (via Electro-Magnetic Articulography, EMA).
Methods
We captured the patterns of articulatory coordination through Principal Component Analysis (PCA) and used Partial Information Decomposition (PID) to identify whether the speech envelope and each of the kinematic components provided unique, synergistic and/or redundant information regarding the EEG signals.
Results
Interestingly, tongue movements contain both unique as well as synergistic information with the envelope that are encoded in brain signals.
Discussions
We demonstrates that during speech listening the brain retrieves highly specific and unique motor information.

目标
语音处理涉及从底层对语音声学近似节奏特性的自下而上驱动与自上而下的调节之间的复杂交互作用，后者引导注意力在时间维度上的分配，并协助选择最相关的输入子空间。自上而下的信号被认为主要源于运动区域，然而，类似的活动也被发现能够调节对简单、非语音刺激的注意力周期。在本研究中，我们探讨了神经信号是否编码了详细的发音信息，这指向了在语音倾听过程中存在一种特定领域的机制。
材料
我们测量了在参与者聆听句子期间脑电图（EEG）数据，同时对于这些句子，我们还获得了嘴唇、颚和舌的发音运动学信息（通过电磁发音术，EMA）。
方法
我们通过主成分分析（PCA）捕捉发音协调的模式，并使用部分信息分解（PID）来确定语音包络和每个运动学组件是否提供了关于脑电信号的独特、协同和/或冗余信息。
结果
有趣的是，舌部运动既包含独特的信息，也包含与包络协同编码在大脑信号中的信息。
讨论
本研究表明，在语音倾听过程中，大脑检索到高度特定和独特的运动信息。