|其他题名||Unitization Reduces Associative Memory Deficits in Older Adults: The Cognitive and Neural Mechanisms|
|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|
|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.
|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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