Soon Chun-Siong, Venkatraman Vinod, Chee Michael W L
Cognitive Neuroscience Laboratory, Singapore General Hospital, Singapore.
Hum Brain Mapp. 2003 Sep;20(1):1-12. doi: 10.1002/hbm.10122.
We investigated the extent of hemodynamic recovery following the paired presentation of either identical or different faces at two different inter-stimulus intervals (ISI). Signal recovery was consistently better at an ISI of 6 sec compared to 3 sec. Significantly less signal recovery was associated with identical faces compared to different faces in bilateral mid-fusiform and right prefrontal regions but not in the calcarine and posterior fusiform regions. Repetition suppression effects contributed significantly to incomplete signal recovery in a region-specific manner. Simulations using empirically derived data suggest that experiments with shorter ISI (average 4.5-6.0 sec) are as sensitive as experiments with intermediate ISI (average 9 sec) in detecting response differences if experimental duration is equivalent. However, designs using intermediate ISI may be more appropriate if the expected difference in responses is small and if the number of suitable stimuli is limited.
我们研究了在两种不同的刺激间隔（ISI）下，呈现相同或不同面孔配对时血流动力学恢复的程度。与3秒的ISI相比，6秒的ISI时信号恢复始终更好。在双侧梭状回中部和右侧前额叶区域，与不同面孔相比，相同面孔的信号恢复明显较少，但在距状裂和梭状回后部区域并非如此。重复抑制效应以区域特异性方式显著导致信号恢复不完全。使用经验得出的数据进行的模拟表明，如果实验持续时间相同，较短ISI（平均4.5 - 6.0秒）的实验在检测反应差异方面与中等ISI（平均9秒）的实验一样敏感。然而，如果预期的反应差异较小且合适刺激的数量有限，使用中等ISI的设计可能更合适。
