Giraud Anne-Lise, Kleinschmidt Andreas, Poeppel David, Lund Torben E, Frackowiak Richard S J, Laufs Helmut
Inserm, U742, Paris, F-75005, France.
Neuron. 2007 Dec 20;56(6):1127-34. doi: 10.1016/j.neuron.2007.09.038.
Across multiple timescales, acoustic regularities of speech match rhythmic properties of both the auditory and motor systems. Syllabic rate corresponds to natural jaw-associated oscillatory rhythms, and phonemic length could reflect endogenous oscillatory auditory cortical properties. Hemispheric lateralization for speech could result from an asymmetry of cortical tuning, with left and right auditory areas differentially sensitive to spectro-temporal features of speech. Using simultaneous electroencephalographic (EEG) and functional magnetic resonance imaging (fMRI) recordings from humans, we show that spontaneous EEG power variations within the gamma range (phonemic rate) correlate best with left auditory cortical synaptic activity, while fluctuations within the theta range correlate best with that in the right. Power fluctuations in both ranges correlate with activity in the mouth premotor region, indicating coupling between temporal properties of speech perception and production. These data show that endogenous cortical rhythms provide temporal and spatial constraints on the neuronal mechanisms underlying speech perception and production.
在多个时间尺度上，言语的声学规律与听觉和运动系统的节律特性相匹配。音节速率对应于与下颌相关的自然振荡节律，音素长度可能反映内源性听觉皮层振荡特性。言语的半球侧化可能源于皮层调谐的不对称，左右听觉区域对言语的频谱-时间特征有不同的敏感性。通过对人类同时进行脑电图（EEG）和功能磁共振成像（fMRI）记录，我们发现γ范围内（音素速率）的自发脑电功率变化与左侧听觉皮层突触活动的相关性最佳，而θ范围内的波动与右侧的相关性最佳。两个范围内的功率波动都与口部运动前区的活动相关，表明言语感知和产生的时间特性之间存在耦合。这些数据表明，内源性皮层节律为言语感知和产生的神经元机制提供了时间和空间限制。
