Ye Zhifang, Zhu Bi, Zhuang Liping, Lu Zhonglin, Chen Chuansheng, Xue Gui
State Key Laboratory of Cognitive Neuroscience and Learning and IDG/McGovern Institute for Brain Research, Beijing Normal University, Beijing 100875, PR China, Center for Collaboration and Innovation in Brain and Learning Sciences, Beijing Normal University, Beijing, 100875, China.
Department of Psychology, Ohio State University, Columbus, Ohio 43210, and.
J Neurosci. 2016 Jun 22;36(25):6792-802. doi: 10.1523/JNEUROSCI.0425-16.2016.
The neural processes giving rise to human memory strength signals remain poorly understood. Inspired by formal computational models that posit a central role of global matching in memory strength, we tested a novel hypothesis that the strengths of both true and false memories arise from the global similarity of an item's neural activation pattern during retrieval to that of all the studied items during encoding (i.e., the encoding-retrieval neural global pattern similarity [ER-nGPS]). We revealed multiple ER-nGPS signals that carried distinct information and contributed differentially to true and false memories: Whereas the ER-nGPS in the parietal regions reflected semantic similarity and was scaled with the recognition strengths of both true and false memories, ER-nGPS in the visual cortex contributed solely to true memory. Moreover, ER-nGPS differences between the parietal and visual cortices were correlated with frontal monitoring processes. By combining computational and neuroimaging approaches, our results advance a mechanistic understanding of memory strength in recognition.
What neural processes give rise to memory strength signals, and lead to our conscious feelings of familiarity? Using fMRI, we found that the memory strength of a given item depends not only on how it was encoded during learning, but also on the similarity of its neural representation with other studied items. The global neural matching signal, mainly in the parietal lobule, could account for the memory strengths of both studied and unstudied items. Interestingly, a different global matching signal, originated from the visual cortex, could distinguish true from false memories. The findings reveal multiple neural mechanisms underlying the memory strengths of events registered in the brain.
产生人类记忆强度信号的神经过程仍未得到充分理解。受形式计算模型的启发，这些模型假定全局匹配在记忆强度中起核心作用，我们测试了一个新假设，即真实记忆和错误记忆的强度都源于检索过程中一个项目的神经激活模式与编码过程中所有学习项目的神经激活模式的全局相似性（即编码 - 检索神经全局模式相似性[ER - nGPS]）。我们揭示了多个携带不同信息且对真实记忆和错误记忆有不同贡献的ER - nGPS信号：顶叶区域的ER - nGPS反映语义相似性，并与真实记忆和错误记忆的识别强度成比例，而视觉皮层中的ER - nGPS仅对真实记忆有贡献。此外，顶叶和视觉皮层之间的ER - nGPS差异与额叶监测过程相关。通过结合计算和神经成像方法，我们的结果推进了对识别中记忆强度的机制理解。
哪些神经过程产生记忆强度信号，并导致我们有意识的熟悉感？使用功能磁共振成像，我们发现给定项目的记忆强度不仅取决于它在学习过程中的编码方式，还取决于其神经表征与其他学习项目的相似性。主要在顶叶小叶中的全局神经匹配信号可以解释学习和未学习项目的记忆强度。有趣的是，源自视觉皮层的不同全局匹配信号可以区分真实记忆和错误记忆。这些发现揭示了大脑中记录事件记忆强度的多种神经机制。
