Department of Psychology, University of California Los Angeles, Los Angeles, CA, 90095, USA.
Department of Psychology, University of California Los Angeles, Los Angeles, CA, 90095, USA.
Neuroimage. 2018 Aug 1;176:110-123. doi: 10.1016/j.neuroimage.2018.04.024. Epub 2018 Apr 11.
Studies of autobiographical memory retrieval often use photographs to probe participants' memories for past events. Recent neuroimaging work has shown that viewing photographs depicting events from one's own life evokes a characteristic pattern of brain activity across a network of frontal, parietal, and medial temporal lobe regions that can be readily distinguished from brain activity associated with viewing photographs from someone else's life (Rissman, Chow, Reggente, and Wagner, 2016). However, it is unclear whether the neural signatures associated with remembering a personally experienced event are distinct from those associated with recognizing previously encountered photographs of an event. The present experiment used a novel functional magnetic resonance imaging (fMRI) paradigm to investigate putative differences in brain activity patterns associated with these distinct expressions of memory retrieval. Eighteen participants wore necklace-mounted digital cameras to capture events from their everyday lives over the course of three weeks. One week later, participants underwent fMRI scanning, where on each trial they viewed a sequence of photographs depicting either an event from their own life or from another participant's life and judged their memory for this event. Importantly, half of the trials featured photographic sequences that had been shown to participants during a laboratory session administered the previous day. Multi-voxel pattern analyses assessed the sensitivity of two brain networks of interest-as identified by a meta-analysis of prior autobiographical and laboratory-based memory retrieval studies-to the original source of the photographs (own life or other's life) and their experiential history as stimuli (previewed or non-previewed). The classification analyses revealed a striking dissociation: activity patterns within the autobiographical memory network were significantly more diagnostic than those within the laboratory-based network as to whether photographs depicted one's own personal experience (regardless of whether they had been previously seen), whereas activity patterns within the laboratory-based memory network were significantly more diagnostic than those within the autobiographical memory network as to whether photographs had been previewed (regardless of whether they were from the participant's own life). These results, also apparent in whole-brain searchlight classifications, provide evidence for dissociable patterns of activation across two putative memory networks as a function of whether real-world photographs trigger the retrieval of firsthand experiences or secondhand event knowledge.
研究自传体记忆检索时，通常会使用照片来探查参与者对过去事件的记忆。最近的神经影像学研究表明，观看描述自己生活事件的照片会在额叶、顶叶和内侧颞叶区域的网络中引起特征性的大脑活动模式，这种模式可以与观看他人生活中的照片所引起的大脑活动轻易区分开来（Rissman、Chow、Reggente 和 Wagner，2016）。然而，尚不清楚与回忆个人经历事件相关的神经特征是否与识别之前遇到的该事件的照片相关的神经特征不同。本实验使用一种新颖的功能磁共振成像（fMRI）范式来研究与这些不同的记忆检索表达相关的大脑活动模式的潜在差异。18 名参与者佩戴项链式数码相机，在三周内记录日常生活中的事件。一周后，参与者接受 fMRI 扫描，在每次试验中，他们观看一系列描述自己生活中的事件或另一参与者生活中的事件的照片，并判断他们对该事件的记忆。重要的是，一半的试验中包含的照片序列在前一天的实验室会议中展示给了参与者。多体素模式分析评估了两个感兴趣的大脑网络的敏感性-通过对先前自传体和基于实验室的记忆检索研究的元分析确定-对照片的原始来源（自己的生活或他人的生活）及其作为刺激的体验史（预览或非预览）。分类分析显示出惊人的分离：自传体记忆网络中的活动模式在判断照片是否描述了自己的个人经历（无论之前是否见过）方面明显比基于实验室的网络中的活动模式更具诊断性，而基于实验室的记忆网络中的活动模式在判断照片是否预览过（无论它们是否来自参与者自己的生活）方面明显比自传体记忆网络中的活动模式更具诊断性。这些结果在全脑搜索灯分类中也很明显，为两个假定的记忆网络中激活模式的可分离性提供了证据，这取决于真实世界的照片是否引发了第一手经验的检索或二手事件知识的检索。
