Center for Neuroscience and Department of Psychology, University of California, Davis, California 95616, USA.
J Neurosci. 2010 Nov 17;30(46):15558-65. doi: 10.1523/JNEUROSCI.1337-10.2010.
One of the defining features of episodic long-term memory is that it includes information about the temporal context in which an event occurred. Little is known about the regions that support the encoding of temporal information in the human brain, although previous work has suggested a role for the lateral prefrontal cortex (PFC) and medial temporal lobes (MTL). Here we used event-related fMRI to examine the relationship between activity at encoding and subsequent memory for temporal context. Participants were scanned while performing a serial order working memory task with pictures of common objects and were later tested for temporal memory at two different timescales. In the coarse temporal memory test, participants viewed one object from each trial and indicated approximately when during the course of the experiment it had appeared. In the fine temporal memory test, participants were shown the remaining objects from each trial and asked to recall the order in which they had been originally presented. Activity in the parahippocampal cortex predicted subsequent fine temporal accuracy, whereas coarse temporal accuracy was predicted by activity in several regions of the PFC, as well as in the hippocampus. Additional multivoxel pattern analyses revealed evidence implicating the rostrolateral PFC in the representation of time-varying contextual states in a manner similar to that proposed by computational theories of temporal context memory. These results highlight MTL and PFC contributions to temporal memory at the time of encoding and suggest a particular role for the rostrolateral PFC in encoding coarse temporal context.
情景性长时记忆的一个定义特征是，它包含了事件发生时的时间背景信息。尽管先前的研究表明外侧前额叶皮层（PFC）和内侧颞叶（MTL）在其中起到了作用，但对于支持人类大脑中时间信息编码的区域知之甚少。在这里，我们使用事件相关 fMRI 来研究编码时的活动与随后的时间背景记忆之间的关系。参与者在执行一个包含常见物体图片的序列顺序工作记忆任务时接受扫描，并在两个不同的时间尺度上接受时间记忆测试。在粗略的时间记忆测试中，参与者从每个试验中查看一个物体，并大致指示它在实验过程中出现的时间。在精细的时间记忆测试中，参与者被展示每个试验中的其余物体，并被要求回忆它们最初呈现的顺序。海马旁回皮层的活动预测了随后的精细时间准确性，而粗时间准确性则由 PFC 的几个区域以及海马体的活动所预测。额外的多体素模式分析表明，额侧外侧 PFC 以类似于时间上下文记忆的计算理论所提出的方式，在表示时变上下文状态方面具有重要作用。这些结果强调了 MTL 和 PFC 在编码时对时间记忆的贡献，并表明额侧外侧 PFC 在编码粗时间背景方面具有特殊作用。
