Modality shift effects mimic multisensory interactions: an event-related potential study
Modality shift effects mimic multisensory interactions: an event-related potential study
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DOI：
10.1007/s00221-007-0982-4
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发表时间：
2007-09-01
影响因子：
2
通讯作者：
Greenlee, Mark W.
中科院分区：
文献类型：
--
作者：
Gondan, Matthias;Vorberg, Dirk;Greenlee, Mark W.
研究听觉和视觉系统相互作用的常用方法是测量听觉、视觉和视觉-听觉刺激（A、V、AV）的事件相关电位（ERP）。AV -（A + V）比较的非零结果表明，感觉系统在特定的处理阶段相互作用。两种可能的偏差削弱了这种方法得出的结论：首先，从一个ERPs中减去两个要求A，V和AV没有任何共同的活动。我们之前已经表明（Gondan和罗德，Brain Res 1073-1074：389-397，2006），使用额外的触觉刺激（T）和评估ERP差异（T + TAV）-（TA + TV）可以避免共同活动的问题。第二个可能的混淆是模态转换效应（MSE）：例如，如果听觉刺激跟随视觉刺激，则听觉N1增加，而如果模态不变（同模态刺激），则听觉N1较小。双峰刺激可能受MSE影响较小，因为至少有一个组件总是匹配前一次试验。因此，在AV中将观察到N1的明显幅度调制。我们通过比较使用（a）所有刺激和使用（B）仅同模刺激的AV -（A + V）结果来测试MSE对视觉-视觉交互的影响。(a)和（B）相差约150 ms，这表明AV -（A + V）确实受到MSE的影响。然后，我们正式和经验证明，（T + TAV）-（TA + TV）是强大的对可能的偏见，由于MSE。
A frequent approach to study interactions of the auditory and the visual system is to measure event-related potentials (ERPs) to auditory, visual, and auditory-visual stimuli (A, V, AV). A nonzero result of the AV -(A + V) comparison indicates that the sensory systems interact at a specific processing stage. Two possible biases weaken the conclusions drawn by this approach: first, subtracting two ERPs from one requires that A, V, and AV do not share any common activity. We have shown before (Gondan and Roder in Brain Res 1073-1074:389-397, 2006) that the problem of common activity can be avoided using an additional tactile stimulus (T) and evaluating the ERP difference (T + TAV) - (TA + TV). A second possible confound is the modality shift effect (MSE): for example, the auditory N1 is increased if an auditory stimulus follows a visual stimulus, whereas it is smaller if the modality is unchanged (ipsimodal stimulus). Bimodal stimuli might be affected less by MSEs because at least one component always matches the preceding trial. Consequently, an apparent amplitude modulation of the N1 would be observed in AV. We tested the influence of MSEs on auditory-visual interactions by comparing the results of AV - (A + V) using (a) all stimuli and using (b) only ipsimodal stimuli. (a) and (b) differed around 150 ms, this indicates that AV - (A + V) is indeed affected by the MSE. We then formally and empirically demonstrate that (T + TAV) - (TA + TV) is robust against possible biases due to the MSE.