Verleger Rolf, Metzner Marvin F, Ouyang Guang, Śmigasiewicz Kamila, Zhou Changsong
Dept. of Neurology, University of Lübeck, Germany.
Dept. of Neurology, University of Lübeck, Germany.
Neuroimage. 2014 Oct 15;100:271-80. doi: 10.1016/j.neuroimage.2014.06.036. Epub 2014 Jun 21.
It has been proposed that the P3b component of event-related potentials (ERPs) reflects linking of responses to target stimuli. This proposal was tested by disconnecting the temporal link between target stimuli and responses, and by applying residue iteration decomposition (RIDE) for separating the ERP components into stimulus-locked, response-locked, and "intermediate" clusters. Left or right keys had to be pressed in response to frequent (80%) and rare (20%) target letters, but responses had to wait for "go" signals (appearing in 90% of trials). Between blocks, stimulus-onset asynchronies (SOAs) from targets to go-signals varied from 0 ms to 800 ms. Rare targets with their rare responses were expected to evoke large P3bs ("oddball effect"). If related to stimulus processing only, this effect will be equally large across all SOAs and will be modeled by RIDE's stimulus-cluster. If related to response initiation only, the oddball effect will be evoked by go-signals rather than by targets and will be modeled by RIDE's response-cluster. If indicating integration of rare stimuli with their rare responses, the oddball effect will be evoked by targets but will be reduced and stretched in time across SOAs and will be modeled by RIDE's intermediate cluster. RIDE analysis confirmed this latter view, for the most part. SOA effects matched best, though not perfectly, predictions made by the stimulus-response-link view. These results call for a refined account of the oddball effect on P3b in terms of stimulus-response coupling.
有人提出，事件相关电位（ERP）的P3b成分反映了对目标刺激的反应关联。通过切断目标刺激与反应之间的时间联系，并应用残差迭代分解（RIDE）将ERP成分分离为刺激锁定、反应锁定和“中间”簇，对这一观点进行了测试。要求被试根据频繁出现（80%）和罕见出现（20%）的目标字母按下左键或右键，但反应必须等待“开始”信号（出现在90%的试验中）。在各实验块之间，从目标到开始信号的刺激起始异步时间（SOA）从0毫秒到800毫秒不等。预期罕见目标及其罕见反应会诱发较大的P3b（“oddball效应”）。如果仅与刺激处理有关，那么这种效应在所有SOA中都将同样大，并且将由RIDE的刺激簇建模。如果仅与反应启动有关，oddball效应将由开始信号而非目标诱发，并将由RIDE的反应簇建模。如果表明罕见刺激与其罕见反应的整合，oddball效应将由目标诱发，但会在SOA中随时间减少并延长，并且将由RIDE的中间簇建模。RIDE分析在很大程度上证实了后一种观点。SOA效应与刺激-反应关联观点所做的预测匹配得最好，尽管并不完美。这些结果要求从刺激-反应耦合的角度对P3b上的oddball效应进行更精细的解释。
