Morishima Yosuke, Akaishi Rei, Yamada Yohei, Okuda Jiro, Toma Keiichiro, Sakai Katsuyuki
Department of Cognitive Neuroscience, Graduate School of Medicine, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo, Japan.
Nat Neurosci. 2009 Jan;12(1):85-91. doi: 10.1038/nn.2237. Epub 2008 Dec 21.
Our voluntary behaviors are thought to be controlled by top-down signals from the prefrontal cortex that modulate neural processing in the posterior cortices according to the behavioral goal. However, we have insufficient evidence for the causal effect of the top-down signals. We applied a single-pulse transcranial magnetic stimulation over the human prefrontal cortex and measured the strength of the top-down signals as an increase in the efficiency of neural impulse transmission. The impulse induced by the stimulation transmitted to different posterior visual areas depending on the domain of visual features to which subjects attended. We also found that the amount of impulse transmission was associated with the level of attentional preparation and the performance of visual selective-attention tasks, consistent with the causal role of prefrontal top-down signals.
我们的自主行为被认为受前额叶皮层自上而下的信号控制，这些信号根据行为目标调节后皮层的神经处理过程。然而，我们尚无足够证据证明自上而下信号的因果效应。我们对人类前额叶皮层施加单脉冲经颅磁刺激，并测量自上而下信号的强度，将其作为神经冲动传递效率的提高。刺激诱发的冲动根据受试者所关注的视觉特征领域传递到不同的后视觉区域。我们还发现，冲动传递量与注意力准备水平及视觉选择性注意任务的表现相关，这与前额叶自上而下信号的因果作用相符。
