一体化编码减少老年人联结记忆损伤的认知神经机制

PSYCH OpenIR > 健康与遗传心理学研究室

	一体化编码减少老年人联结记忆损伤的认知神经机制
其他题名	Unitization Reduces Associative Memory Deficits in Older Adults: The Cognitive and Neural Mechanisms
	郑志伟
	2015-05
摘要	目的：情节记忆是受老化影响较为严重的认知功能之一。大量研究发现，相对于项目记忆，老年人的联结记忆成绩比青年人更差。从情节记忆的双加工理论的角度讲，联结记忆的提取过程极大地依赖于回想，而老年人的回想能力却严重受损，这可能是导致老年人联结记忆下降的原因。然而，新近研究发现，当刺激材料在学习阶段得到一体化编码后，熟悉性也能够支持联结记忆的提取过程。幸运的是，老年人的熟悉性是相对保留的。那么，一体化编码能否减少老化相关的联结记忆损伤？本论文通过三项研究考察了该问题以及老年人一体化编码优势的认知神经机制。方法：采用易于形成一体化表征的言语材料 (如，合成词，语义相关词对等)或指导被试在学习阶段使用一体化编码策略(交互表象法)来创造一体化编码条件。研究一通过比较青年人和老年人在合成词和不相关词对条件下的联结再认成绩，来考察一体化编码能否减少老年人的联结记忆损伤；研究二通过比较两组被试在范畴词对和主题词对条件下的联结再认成绩，来考察一体化编码程度高低是否影响老年人的联结记忆成绩；研究三通过比较两组被试在一体化编码策略条件和非一体化编码策略条件下的来源记忆成绩，来考察一体化编码策略能否改善老年人的来源记忆成绩。在联结记忆提取阶段记录事件相关电位，利用新旧效应来考察熟悉性和回想在联结记忆中的贡献。结果：研究一发现，合成词条件下的联结再认成绩的年龄差异更小，老年人仅在合成词条件下表现出显著的额区新旧效应；研究二发现，主题词对条件下的联结再认成绩的年龄差异更小，老年人在主题词对条件下仅表现出额区新旧效应，在范畴词对条件下则既表现出额区新旧效应也表现出左顶新旧效应；研究三发现，一体化编码策略条件下的来源记忆成绩的年龄差异更小，而额区新旧效应仅在一体化编码策略条件下的来源提取中表现出来。结论：一体化编码能够减少老年人的联结记忆损伤；一体化编码水平越高，老年人的联结记忆成绩越好；老年人的一体化编码优势的可能原因是熟悉性能够支持一体化编码条件下的联结记忆提取。
其他摘要	Objective: Episodic memory is one of the cognitive domains that are vulnerable to aging. A great number of studies have demonstrated that normal aging is associated with greater decline in associative memory relative to item memory. From the perspective of dual-process theories, associative recognition greatly depends on recollection, and disproportionate decline in associative memory relative to item memory in older adults is due to their impaired recollection. Interestingly, recent studies show that familiarity may also contribute to associative recognition when stimuli are perceived as a unitized representation. Given that familiarity is relatively preserved in older adults, we are especially interested in whether age-related associative memory deficits could be attenuated when to-be-remembered stimuli are integrated into a whole unit during encoding. In addition, the present thesis aimed to explore the neurocognitive mechanisms underlying the unitization effects on the associative memory in older adults. Methods: The unitized conditions were created by using the pre-existing associations (e.g., compound words or semantically related word pairs) or by means of an encoding strategy such as creating an interactive and unified mental image between the item and source information. The electroencephalogram (EEG) was recorded, and the contribution of familiarity and recollection to associative memory were qualified by the ERPs old/new effects. Three studies were used to explore the effects of unitization on associative memory in older adults. In study 1, we compared the associative recognition of compound words with unrelated word pairs in young and older adults. In study 2, we compared the associative recognition of categorical word pairs with thematic word pairs in young and older adults. In study 3, we compared the source memory performance under unitized (interactive imagery) and non-unitized (item imagery) encoding condition in young and older adults. Results: In study 1, behavioral results showed that age differences were smaller for recognition of compounds than for unrelated word pairs. ERP results indicated that only compounds evoked an early frontal old/new effect in older adults. In study 2, behavioral results showed that age differences were smaller for recognition of thematic word pairs than for categorical word pairs. ERP results revealed that thematic word pairs only evoked an early frontal old/new effect, and categorical word paris evoked both an early frontal old/new effect and a left parietal old/new effect. In study 3, behavioral results showed that age differences were smaller for the source memory under unitized encoding condition than under non-unitized encoding condition. ERP results indicated that an early frontal old/new effect was evoked only under the unitized condition in older adults. Conclusions: These results suggest that unitization encoding could reduce age-related associative deficits; levels of unitization modulate associative memory performance in older adults; beneficial effect of unitization on associative memory may be associated with the enhanced involvement of familiarity during associative or source retrieval in older adults; these findings have great implications for mnemonic strategies to ameliorate the associative memory impairment in older adults.
学科领域	发展与教育心理学
关键词	老年人联结记忆一体化编码熟悉性回想事件相关电位
学位类型	博士
语种	中文
学位专业	心理学
学位授予单位	中国科学院研究生院
学位授予地点	北京
文献类型	学位论文
条目标识符	http://ir.psych.ac.cn/handle/311026/19786
专题	健康与遗传心理学研究室
作者单位	中国科学院心理研究所
推荐引用方式 GB/T 7714	郑志伟. 一体化编码减少老年人联结记忆损伤的认知神经机制[D]. 北京. 中国科学院研究生院,2015.

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