Redefining the role of Broca's area in speech
Redefining the role of Broca's area in speech
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DOI：
10.1073/pnas.1414491112
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发表时间：
2015-03-03
影响因子：
11.1
通讯作者：
Crone, Nathan E.
中科院分区：
文献类型：
--
作者：
Flinker, Adeen;Korzeniewska, Anna;Crone, Nathan E.
世纪以来，神经科学家们一直在争论人类大脑皮层语言网络是如何让单词被说出的。虽然人们普遍认为左额下回的布罗卡区在这一过程中起着重要作用，但直到最近，才详细说明其相对于其他语言区域的招聘时间，也不知道它在单词产生过程中如何与这些区域相互作用。使用直接皮层表面记录在神经外科患者，我们研究了皮质神经元群体的活动的演变，以及它们之间的格兰杰因果关系的相互作用。我们发现，在线索生产的话，时间级联的神经活动的收益从颞叶皮层的感觉表征的话在运动皮层相应的发音姿势。布罗卡区通过与颞叶和额叶运动区的相互作用来介导这种级联反应。与布洛卡区在言语中作用的经典概念相反，虽然运动皮质在言语反应期间被激活，但布洛卡区却出奇地沉默。此外，当新的字符串的发音手势必须响应于非文字刺激，神经活动增强布罗卡区，但不是在运动皮层。这些独特的数据提供了证据，表明布罗卡区协调了参与口语产生的大规模皮层网络中的信息转换。在这个角色中，布罗卡区制定了一个适当的发音代码，由运动皮层执行。
For over a century neuroscientists have debated the dynamics by which human cortical language networks allow words to be spoken. Although it is widely accepted that Broca's area in the left inferior frontal gyrus plays an important role in this process, it was not possible, until recently, to detail the timing of its recruitment relative to other language areas, nor how it interacts with these areas during word production. Using direct cortical surface recordings in neurosurgical patients, we studied the evolution of activity in cortical neuronal populations, as well as the Granger causal interactions between them. We found that, during the cued production of words, a temporal cascade of neural activity proceeds from sensory representations of words in temporal cortex to their corresponding articulatory gestures in motor cortex. Broca's area mediates this cascade through reciprocal interactions with temporal and frontal motor regions. Contrary to classic notions of the role of Broca's area in speech, while motor cortex is activated during spoken responses, Broca's area is surprisingly silent. Moreover, when novel strings of articulatory gestures must be produced in response to non-word stimuli, neural activity is enhanced in Broca's area, but not in motor cortex. These unique data provide evidence that Broca's area coordinates the transformation of information across large-scale cortical networks involved in spoken word production. In this role, Broca's area formulates an appropriate articulatory code to be implemented by motor cortex.