Bergström Zara M, Velmans Max, de Fockert Jan, Richardson-Klavehn Alan
Department of Psychology, Goldsmiths College, University of London, New Cross, London SE14 6NW, UK.
Brain Res. 2007 Jun 2;1151:119-33. doi: 10.1016/j.brainres.2007.03.014. Epub 2007 Mar 12.
We investigated neurocognitive processes of voluntarily avoiding conscious recollection by asking participants to either attempt to recollect (the Think condition) or to avoid recollecting (the No-Think condition) a previously exposed paired associate. Event-related potentials (ERPs) during Think and No-Think trials were separated on the basis of previous learning success versus failure. This separation yielded temporal and topographic dissociations between early ERP effects of a Think versus No-Think strategy, which were maximal between 200 and 300 ms after stimulus presentation and independent of learning status, and a later learning-specific ERP effect maximal between 500 and 800 ms after stimulus presentation. In this later time-window, Learned Think items elicited a larger late left parietal positivity than did Not Learned Think, Learned No-Think, and Not Learned No-Think items; moreover, Learned No-Think and Not Learned Think items did not differ in late left parietal positivity. Because the late left parietal positivity indexes conscious recollection, the results provide firm evidence that conscious recollection of recollectable information can be voluntarily avoided on an item-specific basis and help to clarify previous neural evidence from the Think/No-Think procedure, which could not separate item-specific from strategic processes.
我们通过要求参与者要么尝试回忆（思考条件），要么避免回忆（不思考条件）之前呈现的配对联想词，来研究自愿避免有意识回忆的神经认知过程。思考和不思考试验期间的事件相关电位（ERP）根据之前学习的成功与否进行区分。这种区分在思考与不思考策略的早期ERP效应之间产生了时间和地形上的分离，这些效应在刺激呈现后200至300毫秒之间最大，且与学习状态无关，以及在刺激呈现后500至800毫秒之间最大的后期特定于学习的ERP效应。在这个较晚的时间窗口中，已学习的思考项目比未学习的思考项目、已学习的不思考项目和未学习的不思考项目引发了更大的晚期左顶叶正波；此外，已学习的不思考项目和未学习的思考项目在晚期左顶叶正波上没有差异。由于晚期左顶叶正波标志着有意识回忆，这些结果提供了确凿的证据，表明可以在特定项目的基础上自愿避免对可回忆信息的有意识回忆，并有助于澄清之前来自思考/不思考程序的神经证据，该证据无法将特定项目的过程与策略性过程区分开来。
