Wagner A D, Koutstaal W, Schacter D L
Department of Psychology, Harvard University, Cambridge, MA 02138, USA.
Philos Trans R Soc Lond B Biol Sci. 1999 Jul 29;354(1387):1307-24. doi: 10.1098/rstb.1999.0481.
To understand human memory, it is important to determine why some experiences are remembered whereas others are forgotten. Until recently, insights into the neural bases of human memory encoding, the processes by which information is transformed into an enduring memory trace, have primarily been derived from neuropsychological studies of humans with select brain lesions. The advent of functional neuroimaging methods, such as positron emission tomography (PET) and functional magnetic resonance imaging (fMRI), has provided a new opportunity to gain additional understanding of how the brain supports memory formation. Importantly, the recent development of event-related fMRI methods now allows for examination of trial-by-trial differences in neural activity during encoding and of the consequences of these differences for later remembering. In this review, we consider the contributions of PET and fMRI studies to the understanding of memory encoding, placing a particular emphasis on recent event-related fMRI studies of the Dm effect: that is, differences in neural activity during encoding that are related to differences in subsequent memory. We then turn our attention to the rich literature on the Dm effect that has emerged from studies using event-related potentials (ERPs). It is hoped that the integration of findings from ERP studies, which offer higher temporal resolution, with those from event-related fMRI studies, which offer higher spatial resolution, will shed new light on when and why encoding yields subsequent remembering.
为了理解人类记忆，确定为什么有些经历被记住而有些被遗忘是很重要的。直到最近，对于人类记忆编码（即信息转化为持久记忆痕迹的过程）的神经基础的深入了解，主要来自对患有特定脑损伤的人类进行的神经心理学研究。功能神经成像方法的出现，如正电子发射断层扫描（PET）和功能磁共振成像（fMRI），为进一步了解大脑如何支持记忆形成提供了新的机会。重要的是，事件相关fMRI方法的最新发展现在允许检查编码过程中神经活动的逐次试验差异，以及这些差异对后续记忆的影响。在这篇综述中，我们考虑PET和fMRI研究对理解记忆编码的贡献，特别强调最近关于差异效应（Dm效应）的事件相关fMRI研究：也就是说，编码过程中神经活动的差异与后续记忆的差异有关。然后，我们将注意力转向使用事件相关电位（ERP）的研究所产生的关于Dm效应的丰富文献。希望将具有更高时间分辨率的ERP研究结果与具有更高空间分辨率的事件相关fMRI研究结果相结合，将为编码何时以及为何产生后续记忆提供新的线索。
