Mecklinger Axel, Johansson Mikael, Parra Mauricio, Hanslmayr Simon
Experimental Neuropsychology Unit, Department of Psychology, Saarland University, 66123, Saarbrücken, Germany.
Brain Res. 2007 Oct 3;1172:110-23. doi: 10.1016/j.brainres.2007.07.070. Epub 2007 Aug 14.
The present study examined whether event-related potential (ERP) memory effects and measures of ongoing EEG activity (power and phase locking) are sensitive to varying source retrieval requirements in recognition memory. ERP old/new effects were obtained in two distinct source-memory tasks. Functionally related EEG power and phase locking effects were found in the delta and theta frequency range. A late posterior negativity (LPN) was larger for old than new responses irrespective of source accuracy. It was also larger when participants were required to judge how they had previously interacted with a recognized picture as compared to judging its study location. This result is consistent with the view that the LPN reflects processes in the service of reconstructing previous episodes by integrating recognized items with task-relevant contextual attributes, and that LPN amplitude is related to the amount of contextual features available for forming such an integrated representation. Phase locking of ongoing delta and theta activity (but not EEG power) was functionally equivalent to LPN amplitude modulations, suggesting that stimulus-induced concentration of delta and theta phases without stimulus-induced power changes may be the neural mechanism of LPN generation. In addition, sustained enhancements of phase-locking precision in the theta range were observed for erroneous and delayed source judgments, suggesting that theta-phase locking is related to the coordination of multiple cortical assemblies in highly demanding task situations.
本研究考察了事件相关电位（ERP）记忆效应以及持续脑电图活动（功率和锁相）指标是否对识别记忆中不同的源检索要求敏感。在两项不同的源记忆任务中获得了ERP新旧效应。在δ和θ频率范围内发现了功能相关的脑电图功率和锁相效应。无论源准确性如何，旧反应的晚期后负波（LPN）都比新反应更大。当参与者被要求判断他们之前如何与一张已识别的图片互动，而不是判断其学习位置时，LPN也更大。这一结果与以下观点一致，即LPN反映了通过将已识别的项目与任务相关的情境属性相结合来重建先前事件的过程，并且LPN幅度与可用于形成这种综合表征的情境特征数量有关。持续的δ和θ活动的锁相（而非脑电图功率）在功能上等同于LPN幅度调制，表明刺激诱发的δ和θ相位集中而无刺激诱发的功率变化可能是LPN产生的神经机制。此外，在错误和延迟的源判断中观察到θ范围内锁相精度的持续增强，表明θ相位锁相与高要求任务情境中多个皮层组件的协调有关。
