Parsing the phonological loop: activation timing in the dorsal speech stream determines accuracy in speech reproduction.
Parsing the phonological loop: activation timing in the dorsal speech stream determines accuracy in speech reproduction.
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DOI：
10.1523/jneurosci.1472-12.2013
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发表时间：
2013-03-27
期刊：
影响因子：
--
通讯作者：
Nagarajan SS
中科院分区：
文献类型：
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作者：
Herman AB;Houde JF;Vinogradov S;Nagarajan SS
尽管有大量的研究和重要的临床相关性，直接的神经证据连接语音感知，短期记忆和生产的语音回路仍然难以捉摸。为了研究这些过程，我们从执行可变长度音节序列再现任务的人类受试者获得了全头脑磁图（MEG）记录。MEG传感器的数据源本地化使用的时间-频率空间自适应滤波器，我们研究的时间过程中的皮质振荡功率和振荡功率与行为的相关性，发病之间的音频刺激和明显的语音反应。我们发现在一个网络的区域主要是在背言语流的行为相关的激活的时间过程之间的解离。特别是，言语工作记忆负荷调制高伽马功率（HGP）在Sylvian-Parial-Temporal（Spt）和Broca区。在整个任务中，HGP和受试者表现之间的相关性的时间过程在这两个区域之间明显交替。我们的研究结果提供了第一个证据的混响输入输出缓冲系统的背流语音感觉运动的整合，最近的语音环路，竞争排队和语音运动控制模型相一致。这些研究结果也揭示了失语症和神经精神疾病的言语功能障碍的潜在来源，确定解剖学和行为分离激活时间窗口成功的语音再现的关键。
Despite significant research and important clinical correlates, direct neural evidence for a phonological loop linking speech perception, short-term memory and production remains elusive. To investigate these processes, we acquired whole-head magnetoencephalographic (MEG) recordings from human subjects performing a variable-length syllable sequence reproduction task. The MEG sensor data was source-localized using a time-frequency spatially adaptive filter, and we examined the time-courses of cortical oscillatory power and the correlations of oscillatory power with behavior, between onset of the audio stimulus and the overt speech response. We found dissociations between time-courses of behaviorally relevant activations in a network of regions falling largely within the dorsal speech stream. In particular, verbal working memory load modulated high gamma power (HGP) in both Sylvian-Parietal-Temporal (Spt) and Broca’s Areas. The time-courses of the correlations between HGP and subject performance clearly alternated between these two regions throughout the task. Our results provide the first evidence of a reverberating input-output buffer system in the dorsal stream underlying speech sensorimotor integration, consistent with recent phonological loop, competitive queuing and speech-motor control models. These findings also shed new light on potential sources of speech dysfunction in aphasia and neuropsychiatric disorders, identifying anatomically and behaviorally dissociable activation time-windows critical for successful speech reproduction.