Teder-Sälejärvi W A, McDonald J J, Di Russo F, Hillyard S A
Department of Neurosciences 0608, School of Medicine, University of California-San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0608, USA.
Brain Res Cogn Brain Res. 2002 Jun;14(1):106-14. doi: 10.1016/s0926-6410(02)00065-4.
Crossmodal integration was studied in humans by presenting random sequences of auditory (brief noise bursts), visual (flashes), and audiovisual (simultaneous noise bursts and flashes) stimuli from a central location at irregular intervals between 600 and 800 ms. The subjects' task was to press a button to infrequent and unpredictable (P=0.15) target stimuli that could be either a more intense noise burst, a brighter flash, or a combination of the two. In accordance with previous studies, behavioral data showed that bimodal target stimuli were responded to much faster and were identified more accurately than the unimodal target stimuli. The neural basis of this crossmodal interaction was investigated by subtracting the ERPs to the auditory (A) and the visual (V) stimuli alone from the ERP to the combined audiovisual (AV) stimuli (i.e. interaction=AV-(A+V)). Using this approach, we replicated previous reports of both early (at around 40 ms) and late (after 100 ms) ERP interaction effects. However, it appears that the very early interaction effects can be largely accounted for by an anticipatory ERP that precedes both the unimodal and bimodal stimuli. In calculating the ERP interaction this slow shift is subtracted twice, resulting in an apparent shift of the opposite polarity that may be confounded with actual crossmodal interactions.
通过从中央位置以600至800毫秒之间的不规则间隔呈现听觉（短暂噪声爆发）、视觉（闪光）和视听（同时的噪声爆发和闪光）刺激的随机序列，对人类的跨模态整合进行了研究。受试者的任务是按下按钮以应对不频繁且不可预测的（P = 0.15）目标刺激，这些目标刺激可以是更强烈的噪声爆发、更明亮的闪光或两者的组合。与先前的研究一致，行为数据表明，与单模态目标刺激相比，双模态目标刺激的反应速度更快，识别更准确。通过从对组合视听（AV）刺激的事件相关电位（ERP）中减去对单独的听觉（A）和视觉（V）刺激的ERP，来研究这种跨模态相互作用的神经基础（即相互作用=AV - （A + V））。使用这种方法，我们重复了先前关于早期（约40毫秒）和晚期（100毫秒后）ERP相互作用效应的报告。然而，似乎非常早期的相互作用效应在很大程度上可以由在单模态和双模态刺激之前出现的预期ERP来解释。在计算ERP相互作用时，这种缓慢的偏移被减去了两次，导致出现了相反极性的明显偏移，这可能与实际的跨模态相互作用混淆。
