Min Byoung-Kyong, Park Jin Young, Kim Eun Joo, Kim Joong Il, Kim Jae-Jin, Park Hae-Jeong
Brain Korea 21 Project for Medical Science, Yonsei University, College of Medicine, Seoul, Republic of Korea.
Neurosci Lett. 2008 Jun 27;438(3):270-4. doi: 10.1016/j.neulet.2008.04.067. Epub 2008 Apr 24.
Since prestimulus EEG alpha activity has recently been considered to convey prestimulus top-down processing, we investigated whether prestimulus alpha activity reflects temporal expectancy of upcoming stimulation even under the non-classical contingent negative variation (CNV) paradigm. EEG was recorded from 16 subjects performing a color and a shape discrimination task manipulated with constant and variable inter-stimulus interval (ISI) conditions. The power of oscillatory activity was investigated by convolving the EEG signals with Morlet wavelets. The constant ISI condition yielded significantly shorter reaction times than the variable ISI condition, indicating more efficient preparation for upcoming stimuli during the constant ISI. We found significantly higher prestimulus alpha activity in the constant ISI condition than in the variable ISI condition, but no significant CNV even in the constant ISI condition. Such a reflection of temporal expectancy in the prestimulus alpha activity corroborates that the prestimulus top-down mental state for preparing upcoming task-performance is considerably reflected in the prestimulus ongoing alpha activity.
由于刺激前脑电图α活动最近被认为可传达刺激前的自上而下的加工过程，我们研究了即使在非经典的关联性负变（CNV）范式下，刺激前α活动是否反映即将到来的刺激的时间预期。记录了16名受试者在执行颜色和形状辨别任务时的脑电图，该任务在恒定和可变刺激间隔（ISI）条件下进行操作。通过将脑电图信号与莫雷小波进行卷积来研究振荡活动的功率。恒定ISI条件下的反应时间明显短于可变ISI条件，表明在恒定ISI期间对即将到来的刺激有更有效的准备。我们发现，恒定ISI条件下的刺激前α活动明显高于可变ISI条件，但即使在恒定ISI条件下也没有明显的CNV。刺激前α活动中这种时间预期的反映证实，用于准备即将到来的任务表现的刺激前自上而下的心理状态在很大程度上反映在刺激前正在进行的α活动中。
