Brainnetome Lecture Series - The transformative nature of human episodic memory
Title: The transformative nature of human episodic memory
Speaker: Prof.Gui Xue, Beijing Normal University, BNU
Chair: Prof.Tianzi Jiang, Brainnetome Center, CASIA
Time: 2021.07.02, 09:30 - 10:30
Venue: The 1rd meeting room, 3rd floor, Intelligence Building
Memory has long been conceived as a dynamic process. As Bartlett (1932) noted, "Remembering is not the re-excitation of innumerable fixed, lifeless and fragmentary traces, but rather an imaginative reconstruction or construction...". Nevertheless, existing studies have largely emphasized the reactivation of encoded neural representations during memory retention and retrieval, whereas the dynamic nature of memory are still poorly understood. To address this question, we employ functional magnetic imaging (fMRI), intracranial electroencephalogram (iEEG) and magnetoencephalography (MEG) imaging technology to examine the neural representations with high spatial and temporal resolutions. In addition, by linking neural representations with deep neural network model, we could infer the representational formats during different memory stages and in different brain regions. Our results suggest that the reactivated representations during long-term memory retrieval have been systematically transformed from the encoded representations, in terms of both the representational formats and the brain regions containing the representations. Furthermore, this representational transformation occurs much faster than previously thought: it starts right after stimulus offset and continue to evolve from short-term memory retention to long-term memory retrieval. Finally, it is suggested that greater representational transformation during encoding is predictive of better longterm memory, and effective learning strategies, such as spaced learning and retrieval practice, often involve greater representational transformation. These results not only help us understand how memory is constructed and reconstructed, but also hold the potential to understand the role of episodic memory in supporting other cognitive functions, such as problem-solving and creative thinking.