Human Sensorimotor Cortex Control of Directly Measured Vocal Tract Movements during Vowel Production
Human Sensorimotor Cortex Control of Directly Measured Vocal Tract Movements during Vowel Production
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DOI：
10.1523/jneurosci.2382-17.2018
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发表时间：
2018-03-21
影响因子：
5.3
通讯作者：
Chang, Edward F.
中科院分区：
文献类型：
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作者：
Conant, David F.;Bouchard, Kristofer E.;Chang, Edward F.
在语言产生过程中，我们以惊人的精度和速度进行声道运动。我们对人类大脑如何实现如此熟练的控制的理解是有限的，部分原因是同时获得高分辨率神经记录和详细的声道测量的挑战。为了克服这一挑战，我们将4名受试者（3名女性，1名男性）的皮层表面皮质电图记录与超声和视频监测结合起来，研究腹侧感觉运动皮层（vSMC）的神经活动与英语元音产生过程中测量的发音运动（位置、速度、速度、加速度）之间的关系。我们发现，在许多单独的vSMC电极上的高伽马活动强烈地编码了一个或多个发音器的运动学，但对元音共振峰和元音同一性的影响较小。神经种群解码方法进一步揭示了区分元音的运动特征结构。发音器运动学编码在时间上呈稀疏分布，主要发生在元音起始和偏移时间。相比之下，在元音的稳定状态部分，编码较低，尽管在一些电极上持续的神经活动。所有的运动参数都有显著的表征，但速度是最稳健的。这些发现通过直接声道监测实现，展示了对语音产生过程中vSMC编码的发音运动学参数表示的新见解。
During speech production, we make vocal tract movements with remarkable precision and speed. Our understanding of how the human brain achieves such proficient control is limited, in part due to the challenge of simultaneously acquiring high-resolution neural recordings and detailed vocal tract measurements. To overcome this challenge, we combined ultrasound and video monitoring of the supralaryngeal articulators (lips, jaw, and tongue) with electrocorticographic recordings from the cortical surface of 4 subjects (3 female, 1 male) to investigate how neural activity in the ventral sensory-motor cortex (vSMC) relates to measured articulator movement kinematics (position, speed, velocity, acceleration) during the production of English vowels. We found that high-gamma activity at many individual vSMC electrodes strongly encoded the kinematics of one or more articulators, but less so for vowel formants and vowel identity. Neural population decoding methods further revealed the structure of kinematic features that distinguish vowels. Encoding of articulator kinematics was sparsely distributed across time and primarily occurred during the time of vowel onset and offset. In contrast, encoding was low during the steady-state portion of the vowel, despite sustained neural activity at some electrodes. Significant representations were found for all kinematic parameters, but speed was the most robust. These findings enabled by direct vocal tract monitoring demonstrate novel insights into the representation of articulatory kinematic parameters encoded in the vSMC during speech production.