尽管海马体涉及记忆的时间组织和场景元素的关联,一些理论解释认为海马在情景记忆中的作用很大程度上是暂时的。在这项研究中,我们着手通过在参与者执行时间顺序记忆任务时识别与场景构建相关的海马活动模式来探索这种差异.功能磁共振成像扫描仪的参与者被展示了一系列照片,每个由中心对象和上下文背景场景组成。在每次检索试验中,向参与者展示了一对原始照片(FULL),没有背景的场景中的对象(OBJ),或没有主前景对象(BACK)的背景上下文。在时间顺序判断(TOJ)任务中,参与者判断了这对场景的时间顺序;在观看试验中,两个相同的场景显示没有任何任务。首先,我们发现前海马体-特别是CA1和下膜-在BACK和OBJ条件之间显示出相似的激活模式,这表明场景构建在TOJ和观看期间都是自发发生的。此外,前海马中场景构建的神经标记不适用于不正确的试验,表明成功的时间记忆检索在功能上与场景构建有关。在大脑皮层,时间处理区域,如辅助运动区和前肌,和场景处理区域,比如海马旁皮层,被激活并与海马体功能连接。一起,这些结果支持海马体同时参与记忆的场景构建和时间组织的观点,并提出了一个考虑这两个过程的海马情景记忆模型。
Although the hippocampus has been implicated in both the temporal organization of memories and association of scene elements, some theoretical accounts posit that the role of the hippocampus in episodic memory is largely atemporal. In this study, we set out to explore this discrepancy by identifying hippocampal activity patterns related to scene construction while participants performed a temporal order memory task. Participants in the fMRI scanner were shown a sequence of photographs, each consisting of a central object and a contextual background scene. On each retrieval trial, participants were shown a pair of the original photographs (FULL), objects from the scenes without the background (OBJ), or background contexts without the main foreground object (BACK). In the temporal order judgment (TOJ) task, participants judged the temporal order of the pair of scenes; in the Viewing trials, two identical scenes were shown without any task. First, we found that the anterior hippocampus-particularly the CA1 and subiculum-showed similar patterns of activation between the BACK and OBJ conditions, suggesting that scene construction occurred spontaneously during both TOJ and Viewing. Furthermore, neural markers of scene construction in the anterior hippocampus did not apply to incorrect trials, showing that successful temporal memory retrieval was functionally linked to scene construction. In the cortex, time-processing areas, such as the supplementary motor area and the precuneus, and scene-processing areas, such as the parahippocampal cortex, were activated and functionally connected with the hippocampus. Together, these results support the view that the hippocampus is concurrently involved in scene construction and temporal organization of memory and propose a model of hippocampal episodic memory that takes both processes into account.