Spatio-Temporal Progression of Cortical Activity Related to Continuous Overt and Covert Speech Production in a Reading Task
Spatio-Temporal Progression of Cortical Activity Related to Continuous Overt and Covert Speech Production in a Reading Task
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DOI：
10.1371/journal.pone.0166872
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发表时间：
2016-11-22
期刊：
影响因子：
3.7
通讯作者：
Schalk, Gerwin
中科院分区：
文献类型：
--
作者：
Brumberg, Jonathan S.;Krusienski, Dean J.;Schalk, Gerwin
人类大脑是如何计划、执行和监控连续流利的语言的，这在很大程度上仍然是难以捉摸的。例如，先前的研究已经确定了对语言功能的不同方面最重要的皮层位置，但尚未对这些位置在语言公开或隐蔽进展时参与的时间进展做出定义。在本文中，我们揭示了与连续显性言语相关的神经元群体水平活动的时空演变，并确定了在显性言语和隐性言语中共享活动特征的位置。具体来说，我们要求受试者大声或无声地重复连续的句子，同时直接记录来自大脑表面的电信号（皮质电图）。然后，我们确定了皮层活动和亚秒时间尺度下不同区域的语言输出之间的关系。研究结果强调了大脑皮层参与连续言语过程的时空进展，该过程在额叶运动区启动话语，并在颞上回监测听觉反馈。直接比较与显性条件和隐性条件相关的皮层活动揭示了涉及语音的共同大脑区域网络，该网络可能执行正字法和语音处理。我们的结果提供了连续语音过程的时空电生理表征的第一个特征之一，也突出了公开和隐蔽语音的共同神经基质。因此，这些结果有助于对人类大脑语言功能的精确理解。
How the human brain plans, executes, and monitors continuous and fluent speech has remained largely elusive. For example, previous research has defined the cortical locations most important for different aspects of speech function, but has not yet yielded a definition of the temporal progression of involvement of those locations as speech progresses either overtly or covertly. In this paper, we uncovered the spatio-temporal evolution of neuronal population-level activity related to continuous overt speech, and identified those locations that shared activity characteristics across overt and covert speech. Specifically, we asked subjects to repeat continuous sentences aloud or silently while we recorded electrical signals directly from the surface of the brain (electrocorticography (ECoG)). We then determined the relationship between cortical activity and speech output across different areas of cortex and at sub-second timescales. The results highlight a spatio-temporal progression of cortical involvement in the continuous speech process that initiates utterances in frontal motor areas and ends with the monitoring of auditory feedback in superior temporal gyrus. Direct comparison of cortical activity related to overt versus covert conditions revealed a common network of brain regions involved in speech that may implement orthographic and phonological processing. Our results provide one of the first characterizations of the spatio-temporal electrophysiological representations of the continuous speech process, and also highlight the common neural substrate of overt and covert speech. These results thereby contribute to a refined understanding of speech functions in the human brain.