title: Transformed Neural Pattern Reinstatement during Episodic Memory Retrieval.
abstract: Contemporary models of episodic memory posit that remembering involves the reenactment of encoding processes. Although encoding-retrieval similarity has been consistently reported and linked to memory success, the nature of neural pattern reinstatement is poorly understood. Using high-resolution fMRI on human subjects, our results obtained clear evidence for item-specific pattern reinstatement in the frontoparietal cortex, even when the encoding-retrieval pairs shared no perceptual similarity. No item-specific pattern reinstatement was found in the ventral visual cortex. Importantly, the brain regions and voxels carrying item-specific representation differed significantly between encoding and retrieval, and the item specificity for encoding-retrieval similarity was smaller than that for encoding or retrieval, suggesting different nature of representations between encoding and retrieval. Moreover, cross-region representational similarity analysis suggests that the encoded representation in the ventral visual cortex was reinstated in the frontoparietal cortex during retrieval. Together, these results suggest that, in addition to reinstatement of the originally encoded pattern in the brain regions that perform encoding processes, retrieval may also involve the reinstatement of a transformed representation of the encoded information. These results emphasize the constructive nature of memory retrieval that helps to serve important adaptive functions.SIGNIFICANCE STATEMENTEpisodic memory enables humans to vividly reexperience past events, yet how this is achieved at the neural level is barely understood. A long-standing hypothesis posits that memory retrieval involves the faithful reinstatement of encoding-related activity. We tested this hypothesis by comparing the neural representations during encoding and retrieval. We found strong pattern reinstatement in the frontoparietal cortex, but not in the ventral visual cortex, that represents visual details. Critically, even within the same brain regions, the nature of representation during retrieval was qualitatively different from that during encoding. These results suggest that memory retrieval is not a faithful replay of past event but rather involves additional constructive processes to serve adaptive functions.
authors.affiliation: State Key Laboratory of Cognitive Neuroscience and Learning and IDG/McGovern Institute of Brain Research, Beijing Normal University, Beijing 100875, PR China.|Center for Collaboration and Innovation in Brain and Learning Sciences, Beijing Normal University, Beijing 100875, PR China.
authors.forename: Xiaoqian
authors.initials: X
authors.lastname: Xiao
authors.affiliation: State Key Laboratory of Cognitive Neuroscience and Learning and IDG/McGovern Institute of Brain Research, Beijing Normal University, Beijing 100875, PR China.|Center for Collaboration and Innovation in Brain and Learning Sciences, Beijing Normal University, Beijing 100875, PR China.
authors.forename: Qi
authors.initials: Q
authors.lastname: Dong
authors.affiliation: Center for MRI Research and Beijing City Key Laboratory for Medical Physics and Engineering, School of Physics and McGovern Institute for Brain Research, Peking University, Beijing 100871, PR China, and.
authors.forename: Jiahong
authors.initials: J
authors.lastname: Gao
authors.affiliation: Center for MRI Research and Beijing City Key Laboratory for Medical Physics and Engineering, School of Physics and McGovern Institute for Brain Research, Peking University, Beijing 100871, PR China, and.
authors.forename: Weiwei
authors.initials: W
authors.lastname: Men
authors.affiliation: Department of Psychology, Stanford University, Stanford, California 94305.
authors.forename: Russell A
authors.initials: RA
authors.lastname: Poldrack
authors.affiliation: State Key Laboratory of Cognitive Neuroscience and Learning and IDG/McGovern Institute of Brain Research, Beijing Normal University, Beijing 100875, PR China, guixue@gmail.com.|Center for Collaboration and Innovation in Brain and Learning Sciences, Beijing Normal University, Beijing 100875, PR China.
authors.forename: Gui
authors.identifier: 0000-0001-7891-8151
authors.initials: G
authors.lastname: Xue
mesh_terms: D000293:Adolescent; D000328:Adult; D001288:Attention / Q000502:physiology; D001931:Brain Mapping; D005260:Female; D005625:Frontal Lobe / Q000502:physiology*; D006801:Humans; D061212:Memory, Episodic; D011939:Mental Recall / Q000502:physiology*; D009415:Nerve Net / Q000502:physiology; D009473:Neuronal Plasticity / Q000502:physiology*; D010296:Parietal Lobe / Q000502:physiology*; D010364:Pattern Recognition, Visual / Q000502:physiology*; D055815:Young Adult
keywords: episodic memory; reinstatement; representational pattern similarity