Gomes Carlos Alexandre, Mecklinger Axel, Zimmer Hubert
Department of Psychology, Saarland University, Saarbrücken, Germany.
Cortex. 2017 Jul;92:271-288. doi: 10.1016/j.cortex.2017.04.008. Epub 2017 Apr 21.
It has been recently suggested that fluency may impact recognition memory performance when the fluency context varies from trial-to-trial. Surprisingly, such an effect has proved difficult to detect in the masked priming paradigm, one of the most popular means to increase fluency-based memory judgements. We conducted a functional magnetic resonance imaging (fMRI) experiment in which participants encoded words at study and, at test, performed a recognition memory task within a masked priming procedure. In order to optimise the chances of finding priming effects on recognition memory performance, we used low-frequency words, which have been shown to increase hits relative to false alarms and enhance masked priming effects. Fluency context was manipulated by either mixing primed and unprimed trials [Random context (RC) experiment] or blocking primed and unprimed trials [Blocked context (BC) experiment]. Behaviourally, priming affected high-confidence memory performance only in the RC experiment. This behavioural effect correlated positively with neural priming in several recognition memory regions. Moreover, we observed a functional coupling between the left middle temporal gyrus and the left parietal and posterior cingulate cortices that was greater for primed relative to unprimed words. In contrast, in the BC experiment, despite similar activity in recognition-memory-related regions, we did not find any significant correlations between neural and behavioural priming. Finally, we observed striking differences in the neural correlates of masked priming between the RC and BC experiments not only in location but also in direction of the neural response. Possible implications of these findings are discussed.
最近有人提出，当流畅性情境在不同试验间变化时，流畅性可能会影响识别记忆表现。令人惊讶的是，在掩蔽启动范式（这是增加基于流畅性的记忆判断的最常用方法之一）中，这种效应很难被检测到。我们进行了一项功能磁共振成像（fMRI）实验，参与者在学习阶段对单词进行编码，在测试阶段，在掩蔽启动程序中执行识别记忆任务。为了优化发现启动对识别记忆表现影响的可能性，我们使用了低频单词，研究表明低频单词相对于错误警报会增加命中次数并增强掩蔽启动效应。通过混合启动和未启动试验[随机情境（RC）实验]或阻断启动和未启动试验[阻断情境（BC）实验]来操纵流畅性情境。在行为上，启动仅在RC实验中影响高置信度记忆表现。这种行为效应与几个识别记忆区域的神经启动呈正相关。此外，我们观察到左侧颞中回与左侧顶叶和后扣带回皮质之间存在功能耦合，启动单词相对于未启动单词的这种耦合更强。相比之下，在BC实验中，尽管与识别记忆相关区域的活动相似，但我们没有发现神经启动与行为启动之间存在任何显著相关性。最后，我们观察到RC和BC实验之间掩蔽启动的神经相关性不仅在位置上，而且在神经反应方向上都存在显著差异。我们讨论了这些发现的可能含义。
