Grenoble Institut des Neuroscience, INSERM U 836, 38042 Grenoble, France.
J Neurosci. 2011 Feb 16;31(7):2712-7. doi: 10.1523/JNEUROSCI.3433-10.2011.
Subcortical-cortical interactions in the language network were investigated using dynamic causal modeling of magnetoencephalographic data recorded during auditory comprehension. Participants heard sentences that either were correct or contained violations. Sentences containing violations had syntactic or prosodic violations or both. We show that a hidden source, modeling magnetically silent deep nuclei, is required to explain the data best. This is in line with recent brain imaging studies and intracranial recordings suggesting an involvement of subcortical structures in language processing. Here, the processing of syntactic and prosodic violations elicited a global increase in the amplitude of evoked responses, both at the cortical and subcortical levels. As estimated by Bayesian model averaging, this was accompanied by various changes in cortical-cortical and subcortical-cortical connectivity. The most consistent findings in relation to violations were a decrease of reentrant inputs to Heschl's gyrus (HG) and of transcallosal lateral connections. These results suggest that in conditions where one hemisphere detects a violation, possibly via fast thalamocortical (HG) loops, the intercallosal connectivity is reduced to allow independent processing of syntax (left hemisphere) and of prosody (right hemisphere). This study is the first demonstration in cognitive neuroscience that subcortical-cortical loops can be empirically investigated using noninvasive electrophysiological recordings.
使用听觉理解期间记录的脑磁图数据的动态因果建模研究语言网络中的皮质下-皮质相互作用。参与者听到的句子要么正确，要么包含违规。包含违规的句子有句法或韵律违规或两者兼有。我们表明，需要隐藏源（建模磁静默的深部核）来最佳地解释数据。这与最近的脑成像研究和颅内记录一致，表明皮质下结构参与语言处理。在这里，处理句法和韵律违规会引起诱发反应幅度的全局增加，无论是在皮质和皮质下水平。如贝叶斯模型平均估计，这伴随着皮质内和皮质下皮质内连接的各种变化。与违规最相关的发现是，Heschl 回（HG）的返回复入输入和胼胝体横向连接减少。这些结果表明，在一个半球通过可能通过快速丘脑皮质（HG）环检测到违规的情况下，为了允许对句法（左半球）和韵律（右半球）进行独立处理，减少了连合间连接。这项研究首次在认知神经科学中证明，可以使用非侵入性电生理记录来经验性地研究皮质下-皮质循环。
