Verleger Rolf, Grauhan Nils, Śmigasiewicz Kamila
Department of Neurology, University of Lübeck, Lübeck, Germany.
Institute of Psychology II, University of Lübeck, Lübeck, Germany.
Psychophysiology. 2016 Dec;53(12):1858-1869. doi: 10.1111/psyp.12756. Epub 2016 Sep 4.
P3b is a prominent component of human event-related EEG potentials. P3b has been related to consciousness, encoding into memory, and updating of strategic schemata, among others, yet evidence has also been provided for its close relationship with deciding how to respond to the presented stimuli. P3b is large with rarely occurring stimuli and small with frequent ones. Here, we investigate the extent to which this oddball effect depends on selecting and executing responses. Participants pressed one of two keys in response to one of two letters, one of which was presented rarely and one frequently. Information about letter-key mapping was provided by a second stimulus. In different blocks, this mapping stimulus was either constant across trials or varied randomly, and either preceded or followed the letter. The oddball effect was reduced when responses were delayed (by waiting for the constant mapping stimulus following the letter) and was further reduced when responses could not be assigned to the letters (because letters were followed by varying mapping stimuli). This evidence suggests that P3b is closely related to decision processes, possibly reflecting reactivation of stimulus-response links.
P3b是人类事件相关脑电图电位的一个显著成分。P3b与意识、编码进入记忆以及策略图式的更新等有关，此外，也有证据表明它与决定如何对呈现的刺激做出反应密切相关。对于罕见出现的刺激，P3b较大；而对于频繁出现的刺激，P3b较小。在此，我们研究这种奇偶数效应在多大程度上依赖于选择和执行反应。参与者根据两个字母之一按下两个按键中的一个，其中一个字母很少出现，另一个频繁出现。关于字母 - 按键映射的信息由第二个刺激提供。在不同的组块中，这个映射刺激在各次试验中要么保持不变，要么随机变化，并且要么在字母之前呈现，要么在字母之后呈现。当反应延迟时（通过等待字母之后的恒定映射刺激），奇偶数效应减小；当反应无法与字母对应时（因为字母之后是变化的映射刺激），奇偶数效应进一步减小。这一证据表明P3b与决策过程密切相关，可能反映了刺激 - 反应联系的重新激活。
