• Research Progress
  • Prof. Xue published TICS feature review on memory(single-author)
    On April 2016, Trends in Cognitive Sciences online published a feature review paper entitled "The Neural Representations Underlying Human Episodic Memory " by Prof. Gui Xue.
    One fundamental question in learning and memory concerns the cognitive and neural representations and processes that give rise to the neural signal of episodic memory? Due to methodological limitations, early neuroimaging studies primarily relied on univariate brain activation as neural measures of memory signals. Recent studies combining neural activation patterns and computational models enable a more mechanistic understanding of the neural representations and processes that give rise to human episodic memory. In this review, we examined what aspects of representations during encoding and retrieval contribute to episodic memory and mnemonic decisions. We then focuses on the emerging evidence showing the interactions between representations, including the interaction between the representation of an event during encoding and that during retrieval, between the representation of a given event and that of other events in episodic memory space, and between the representation of an event and pre-existing long-term knowledge (Figure 1). This framework highlights the interactive nature of human episodic memory.

    Figure 1. Schematic Depiction of the Interactive Nature of Human Episodic Memory.
    This work is also a summary of the recent work conducted in Prof. Xue’s lab. In his early Science article published in 2010, Prof. Xue reported that better subsequent memory performance was accompanied by greater neural pattern similarity during encoding. This finding led to the “neural pattern reinstatement” hypothesis for effective learning. Several lines of following up studies further strengthen and expanded this hypothesis. (1) Using EEG technique that offering high temporal resolution, Lu et al (2015) provided evidence that pattern similarity during repeated studies reflected study-phase retrieval, which supports effective memory encoding. (2) The neural pattern similarity is an important factor that underlies the memory decline during normal aging (Zheng et al., 2017), which could be enhanced by prefrontal cortex activity (Xue et al., 2013; Lu et al., 2015; Zheng et al., 2017). (3) Neural pattern during encoding reinstates in multiply brain regions during memory retrieval, as measured by encoding – retrieval neural pattern similarity. Importantly, the pattern reinstated was not a precise reply of the encoded memory representations, but rather reflected a more constructive process (Xiao et al., 2017). (4) By leveraging the neural global pattern similarity analysis, two studies examined the interactions between memory representation of encoding items and representations of other events in episodic memory space. The global pattern similarity could explain the animacy effect on memory (Xiao et al., 2016) and the formation of false memory (Ye et al., 2016). (5) Anodal tDCS on prefrontal cortex could enhance neural pattern reinstatement and improve memory performance (Lu et al,. 2015). Together, these evidence suggest that the neural pattern reinstatement hypothesis may provide a fundamental mechanism for a broad range of memory phenomenon,
    This work was sponsored by the National Natural Science Foundation of China (NSFC; grant 31730038), the 973 Program (2014CB846102), and the NSFC and the German Research Foundation (DFG) joint project NSFC61621136008/DFG TRR-169.

    Xue, G. (2018). The Neural Representations Underlying Human Episodic Memory. Trends in Cognitive Sciences

    Xue, G., Dong, Q., Chen, C., Lu, Z., Mumford, J. A., & Poldrack, R. A. (2010). Greater neural pattern similarity across repetitions is associated with better memory. Science330(6000), 97-101.

    Xue, G., Dong, Q., Chen, C., Lu, Z. L., Mumford, J. A., & Poldrack, R. A. (2012). Complementary role of frontoparietal activity and cortical pattern similarity in successful episodic memory encoding. Cerebral Cortex23(7), 1562-1571.

    Lu, Y., Wang, C., Chen, C., & Xue, G. (2015). Spatiotemporal neural pattern similarity supports episodic memory. Current Biology25(6), 780-785.

    Ye, Z., Zhu, B., Zhuang, L., Lu, Z., Chen, C., & Xue, G. (2016). Neural global pattern similarity underlies true and false memories. Journal of Neuroscience36(25), 6792-6802.

    Xiao, X., Dong, Q., Chen, C., & Xue, G. (2016). Neural pattern similarity underlies the mnemonic advantages for living words. Cortex79, 99-111.

    Xiao, X., Dong, Q., Gao, J., Men, W., Poldrack, R. A., & Xue, G. (2017). Transformed neural pattern reinstatement during episodic memory retrieval. Journal of Neuroscience37(11), 2986-2998.

    Zheng, L., Gao, Z., Xiao, X., Ye, Z., Chen, C., & Xue, G. (2017). Reduced fidelity of neural representation underlies episodic memory decline in normal aging. Cerebral Cortex, 1-14.