| 其他摘要 | Episodic memory refers to people's memory of an event according to the connection between time and space. Episodic memory plays a vital role in maintaining individual experience and accumulating and storing direct experience, which has important value. Context information is an important part of episodic memory, and the distinction between item and context information is not a simple binary relationship. As for the role of context information in episodic memory, context overlap effect (hereinafter referred to as context effect) found that the overlap of context information during encoding and extraction has a certain enhancement effect on the memory of target information. However, previous studies focused on young participants, and there was little evidence on the electrophysiological mechanism behind context effect. However, for the context effect of the elderly, the indicators are not comprehensive and the explanation is not sufficient. For the electrophysiological mechanism behind it, there is no relevant electrophysiological research to provide direct evidence. Whether the context effect has age difference is also unclear; Furthermore, it is not clear whether older adults are mainly dependent on different retrieval patterns of episodic memory than younger adults, and whether the electrophysiological mechanisms that cause the context effect are different.
Therefore, in this study, object-context combination pictures were used as stimulus materials to carry out experiments among young and old Chinese participants, and to investigate participants' recognition of objects in new and old contexts. At the same time, ERP (Event-related Potentials) technique was used to record the potentials at the stage of episodic memory extraction. It is expected to explore whether there is a certain age difference in the context effect of episodic memory, and use ERP components to reflect the electrophysiological mechanism of context and age affecting episodic memory extraction.
The behavioral results show that context effect has a certain age difference, young and old people get considerable memory benefit from context effect, but also show different response bias; ERP results show that there are different electrophysiological mechanisms behind context effect in old and young people, which represent different episodic memory extraction processes. For young people, context change affects the old/new effect distributed in the top region, and the old/new effect distributed in the top region is greater in the old context of young people. Context change mainly affects the retrieval process of episodic memory based on recall. For the elderly, the old/new effect distributed in the parietal region is small, and the old/new effect distributed in the frontal region is relatively small. Recall is not the process of episodic memory extraction that the elderly mainly rely on, and is not affected by context change. In contrast, the elderly showed a wide distribution of late slow waves, and the late slow waves were affected by context change in the late time window. The elderly in the old context had a greater degree of late slow waves, and the context change mainly affects a kind of episodic memory extraction process based on compensatory shallow perceptual information extraction in the elderly. The results of the combined analysis of behavior and ERP show that there is a significant correlation between the EEG context effect index and the behavioral context effect index of the elderly, which indicates that the ERP index concerned in this study can effectively explain the electrophysiological mechanism behind the context effect, which verifies the reliability of the study.
In summary, this study found that context effect has a certain age difference, and both young and old people can benefit from context effect memory while showing different response bias. Event-related potentials revealed different electrophysiological mechanisms of context effect in young and old people, and discovered different episodic memory extraction processes in young and old people affected by context. The results of this study provide more theoretical support and reference for the subsequent research on the context effect of episodic memory, and also reveal the existence of different episodic memory extraction processes between the elderly and the young. The elderly show serious decline in episodic memory with aging, resulting in certain social problems and economic burdens. On this basis, the unique episodic memory extraction methods of the elderly, which are different from those of the young, have unique theoretical and practical significance, and provide greater development space for future research. |
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