Sambeth A, Maes J H R, Brankack J
NICI/Department of Biological Psychology, University of Nijmegen, P.O. Box 9104, 6500 HE Nijmegen, The Netherlands.
Neurosci Lett. 2004 Apr 15;359(3):143-6. doi: 10.1016/j.neulet.2004.01.064.
Previous research, using short inter-stimulus intervals (1-4 s), suggests that the P300 of the human event-related potential during oddball and single-stimulus tasks is mainly affected by target-to-target interval (TTI). The present study tested the validity of this claim at longer intervals in a learning task. Participants were assigned to either an oddball task with an inter-stimulus interval (ISI) of 9-20 s or a single-stimulus task with an ISI of 9-20 or 40-90 s and had to learn when to respond to the stimuli. In the oddball task, the target elicited larger amplitudes than did the standard. When comparing the stimuli from the short- and long-ISI conditions with the target from the oddball condition, it was found that the P300 was more positive at long-ISI stimuli than at short-ISI stimuli or oddball targets, and short-ISI stimuli and oddball targets elicited equally large P300 amplitudes. These results suggest that, in oddball tasks with long intervals, besides cognitive factors, ISI rather than TTI affects the P300 amplitude.
以往使用短刺激间隔（1 - 4秒）的研究表明，在oddball任务和单刺激任务期间，人类事件相关电位的P300主要受目标间间隔（TTI）影响。本研究在学习任务中以更长的间隔测试了这一说法的有效性。参与者被分配到刺激间隔（ISI）为9 - 20秒的oddball任务或ISI为9 - 20秒或40 - 90秒的单刺激任务，并必须学会何时对刺激做出反应。在oddball任务中，目标引发的波幅比标准刺激更大。当将短ISI条件和长ISI条件下的刺激与oddball条件下的目标进行比较时，发现长ISI刺激下的P300比短ISI刺激或oddball目标下的P300更正，且短ISI刺激和oddball目标引发的P300波幅大小相同。这些结果表明，在间隔较长的oddball任务中，除了认知因素外，ISI而非TTI会影响P300波幅。
