Department of Psychology, Harvard University, Cambridge, Massachusetts.
Hippocampus. 2013 Dec;23(12):1150-61. doi: 10.1002/hipo.22152. Epub 2013 Jul 10.
Imagining future events and remembering past events rely on a common core network, but several regions within this network--including the hippocampus--show increased activity for imagining future events compared to remembering past events. It remains unclear whether this hippocampal activity reflects processes related to the demands of constructing details retrieved across disparate episodic memories into coherent imaginary events, encoding these events into memory, novelty detection, or some combination of these processes. We manipulated the degree of constructive processing by comparing activity associated with the initial construction of an imagined scenario with the re-construction of an imagined scenario (imagine vs. re-imagine). After accounting for effects of novelty and subsequent memory, we found that a region in the hippocampus was preferentially activated for newly constructed imagined events compared with re-imagined events. Our results suggest that the hippocampus may support several distinct but related processes that are critical for imagining future events, and they also indicate that a particular region within posterior hippocampus may uniquely contribute to the construction of imagined future events.
想象未来事件和回忆过去事件依赖于一个共同的核心网络，但该网络中的几个区域——包括海马体——在想象未来事件时比回忆过去事件表现出更高的活动。目前尚不清楚这种海马体活动是否反映了与将来自不同情景记忆的细节构建到连贯的想象事件中、将这些事件编码到记忆中、新颖性检测或这些过程的某种组合相关的过程。我们通过比较想象场景的初始构建与想象场景的重新构建（想象与再想象）所关联的活动，来操纵构建处理的程度。在考虑了新颖性和后续记忆的影响后，我们发现海马体中的一个区域在新构建的想象事件中比重新想象的事件更活跃。我们的结果表明，海马体可能支持对想象未来事件至关重要的几个不同但相关的过程，并且还表明海马体后区的特定区域可能对构建想象未来事件具有独特的贡献。
