Institute for Biomagnetism and Biosignalanalysis, University of Münster, Germany.
Neuroimage. 2010 Jun;51(2):877-87. doi: 10.1016/j.neuroimage.2010.02.043. Epub 2010 Feb 24.
Conflict and inhibition are considered to exert strong influences on the neurophysiological N200 and P300 brain responses as evoked in go/nogo and stop-signal tasks. In order to separate their underlying neural and functional mechanisms, the current experiment manipulated both conflict and inhibition. To do so, the go/nogo and stop-signal tasks were merged into one paradigm. Conflict was manipulated by varying go-trial frequencies across blocks (75% vs. 25%). Motor inhibition was manipulated by using go, nogo and stop trials each representing a different load of inhibition. Event-related potentials (ERPs) as well as current density reconstructions (CDRs) of fifteen healthy participants were analyzed. Overall, infrequent trials evoked significantly more pronounced N200s than frequent trials. The P300 predominantly revealed significant variations between trial types (go, nogo, stop). Estimated source activations of the MCC and the IFC supported the ERP results; N200-related effects were revealed in both regions, whereas the condition-specific variations of the P300 were only observed in the IFC. The results indicate that the N200 primarily reflects conflict-related effects whereas the P300 predominantly represents motor inhibition.
冲突和抑制被认为对神经生理 N200 和 P300 脑反应有强烈影响，这些反应是在 go/nogo 和停止信号任务中诱发的。为了分离它们潜在的神经和功能机制，当前的实验同时操纵了冲突和抑制。为此，将 go/nogo 和停止信号任务合并到一个范式中。通过在块之间改变 go 试验频率（75%对 25%）来操纵冲突。运动抑制通过使用 go、nogo 和停止试验来操纵，每个试验代表不同的抑制负荷。对 15 名健康参与者的事件相关电位（ERPs）和电流密度重建（CDRs）进行了分析。总体而言，不频繁的试验比频繁的试验引起的 N200 更为显著。P300 主要揭示了试验类型（go、nogo、stop）之间的显著变化。MCC 和 IFC 的估计源激活支持了 ERP 结果；N200 相关效应在两个区域都有发现，而 P300 的条件特异性变化仅在 IFC 中观察到。结果表明，N200 主要反映与冲突相关的效应，而 P300 主要代表运动抑制。
