Department of Epileptology, University of Bonn, D-53105 Bonn, Germany.
J Neurosci. 2011 Apr 6;31(14):5392-7. doi: 10.1523/JNEUROSCI.3668-10.2011.
Not only poststimulus, but also prestimulus neural activity has been shown to be predictive for later successful memory encoding. However, it is still not clear which medial temporal lobe processes precede effective memory formation. Here, our aim was to investigate whether such prestimulus markers for successful memory encoding can be specified based on intracranial recordings directly from the hippocampus and rhinal cortex. For this purpose, we analyzed subsequent memory effects during a continuous word recognition paradigm in 31 presurgical epilepsy patients. We found that rhinal and hippocampal theta and successive alpha power enhancement before word presentation predicted successful memory encoding. Previous studies suggest that stimulus-triggered hippocampal theta activity is particularly related to memory retrieval and activation of a mnemonic context, whereas the alpha rhythm reflects inhibitory top-down control of task processing and executive functioning. In line with these suggestions, we propose that the observed medial temporal theta and alpha power increases before stimulus presentation reflect activation of contextual information and inhibitory top-down control processes preparing for stimulus-triggered memory processing.
不仅是刺激后的神经活动，刺激前的神经活动也被证明可以预测后续成功的记忆编码。然而，目前仍不清楚内侧颞叶的哪些过程先于有效的记忆形成。在这里，我们的目的是研究是否可以基于直接从海马体和内嗅皮层获得的颅内记录来确定成功记忆编码的这种刺激前标记物。为此，我们在 31 名接受手术的癫痫患者中分析了连续单词识别范式期间的后续记忆效应。我们发现，单词呈现前的内嗅和海马θ波和连续的α波功率增强可以预测成功的记忆编码。先前的研究表明，刺激触发的海马θ活动与记忆检索和记忆上下文的激活特别相关，而α节律反映了任务处理和执行功能的抑制性自上而下控制。与这些建议一致，我们提出观察到的刺激前内侧颞叶θ和α波功率增加反映了上下文信息的激活和抑制性自上而下控制过程，为刺激触发的记忆处理做准备。
