Reaction time data and statistical analysis.

We used a data-driven approach to study the electrophysiological correlates of the working memory subprocesses revealed by the reference-back paradigm. In the absence of prior research, we focused on how aging affects the four subprocesses: updating, substitution, gate opening, and gate closing. We conducted our experiment with 24 younger adults (M = 20.17±1.47) and 23 older adults (M = 67.35±4.01). Significant reaction time costs were observed for all four subprocesses, but age-related differences were found only in substitution, which was larger in older than younger adults, indicating it as being the most vulnerable subprocess in aging. Using difference waves, we identified event-related potential components that characterize the subprocesses we studied. Regarding updating: three occipital negativities between 80–180 ms, 300–400 ms, and 400–1,000 ms were observed, with only the latter range showing age group differences. Source analysis showed larger activity differences in the right frontal and temporal areas for younger adults. Regarding substitution: a frontal positivity between 250–600 ms emerged in younger adults, while a posterior positivity between 550–750 ms was found in older adults indicating different underlying processes supported by sLORETA results. Regarding gate opening: three parieto-occipital components were identified: a negativity between 150–250 ms, a positivity between 300–500 ms, and a positivity between 500–700 ms, all showing age-related differences. Regarding gate closing: we found an occipital negativity between 150–300 ms and a frontal positivity between 300–600 ms, neither of which changed between the age groups. From our findings, we conclude that the process of protecting information (gate closing) remains stable with age, despite older adults’ sensitivity to interference. Conversely, we observed age-related differences in gate opening, which may have led to different strategies being used by the two age groups during substitution (the process by which new information is incorporated into working memory), as reflected in the distinct brain activity patterns observed.

本研究采用数据驱动方法，探究参照回溯范式（reference-back paradigm）所揭示的工作记忆子过程的电生理关联。鉴于尚无相关前期研究，本研究聚焦于衰老如何影响四大工作记忆子过程：更新（updating）、替换（substitution）、闸门开启（gate opening）与闸门关闭（gate closing）。本实验招募24名青年被试（年龄均值±标准差：20.17±1.47）与23名老年被试（年龄均值±标准差：67.35±4.01）。实验结果显示，四大子过程均出现显著的反应时损耗，但仅替换子过程存在年龄相关差异：老年被试的反应时损耗显著大于青年被试，提示该子过程是衰老过程中最易受损的工作记忆子过程。本研究通过差异波分析，识别出表征本研究所涉各工作记忆子过程的事件相关电位（event-related potential, ERP）成分。关于更新子过程：本研究观测到三个时段的枕叶负波，分别为80~180 ms、300~400 ms与400~1000 ms，仅最后一个时段的脑电活动存在年龄组差异。源定位分析显示，青年被试的右侧额叶与颞叶区域存在更显著的活动差异。关于替换子过程：青年被试在250~600 ms时段出现额叶正波，而老年被试则在550~750 ms时段出现后部正波；标准化低分辨率脑电磁断层成像（sLORETA）结果提示，两类被试所依赖的底层认知过程存在差异。关于闸门开启子过程：本研究识别出三个顶枕区成分，分别为150~250 ms时段的负波、300~500 ms时段的正波及500~700 ms时段的正波，所有成分均存在年龄相关差异。关于闸门关闭子过程：本研究观测到150~300 ms时段的枕叶负波与300~600 ms时段的额叶正波，两类年龄组间这两种成分均无显著差异。综合本研究结果可知，尽管老年被试对干扰刺激更为敏感，但信息保护过程（即闸门关闭子过程）并未随衰老出现显著变化。与之相反，闸门开启子过程存在显著的年龄相关差异，这可能导致两类被试在替换子过程（即将新信息整合至工作记忆的过程）中采用了不同的认知策略，这一结论与本研究观测到的差异化脑活动模式相一致。