Impulse Propagation along Thalamocortical Fibers Can Be Detected Magnetically outside the Human Brain
Impulse Propagation along Thalamocortical Fibers Can Be Detected Magnetically outside the Human Brain
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DOI：
10.1523/jneurosci.3022-08.2008
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发表时间：
2008-11-19
影响因子：
5.3
通讯作者：
Hashimoto, Isao
中科院分区：
文献类型：
--
作者：
Kimura, Tomoaki;Ozaki, Isamu;Hashimoto, Isao
在人类（Knight，2007）和猴子（Saalmann et al.，2007; Womelsdorf等人，2007年）。振荡活动的频率在很大程度上取决于连接参与振荡的神经区域的神经束的长度和传导速度（Buzsaki，2006）。然而，脉冲在白色物质中沿着纤维束的传播在人类中从未被可视化。在这里，我们表明，通过记录脑磁图（MEG）后正中神经刺激，磁场分量，我们标记为“M15”，动态变化的发病前1.6-1.8毫秒的磁M20反应产生的初级体感皮层。这个新的M15分量对应于以29 m/s的平均传导速度传播的丘脑皮质纤维中的细胞内去极化动作电流。这一发现挑战了传统的观点，即MEG对深层皮层下结构的活动是盲目的。我们认为，脑磁图技术持有的承诺，提供新的信息，脉冲传输沿着不仅丘脑皮质通路，但也在人类其他纤维束连接遥远的大脑区域。
Orchestrating cortical network activity with synchronous oscillations of neurons across distant regions of the brain underlies information processing in humans (Knight, 2007) and monkeys (Saalmann et al., 2007; Womelsdorf et al., 2007). Frequencies of oscillatory activities depend, to a considerable extent, on the length and conduction velocity of the tracts connecting the neural areas that participate in oscillations (Buzsaki, 2006). However, the impulse propagation along the fiber tracts in the white matter has never been visualized in humans. Here, we show, by recording magnetoencephalogram (MEG) following median nerve stimulation, that a magnetic field component, we labeled " M15," changes dynamically within 1.6-1.8 ms before the onset of magnetic M20 response generated from the primary somatosensory cortex. This new M15 component corresponds to the intracellular depolarizing action current in the thalamocortical fibers propagating with the mean conduction velocity of 29 m/s. The findings challenge the traditional view that MEG is blind to the activity of deep subcortical structures. We argue that the MEG technique holds the promise of providing novel information in impulse transmissions along not only the thalamocortical pathway but also other fiber tracts connecting distant brain areas in humans.