Maillet David, Rajah M Natasha
Harvard University.
McGill University.
J Cogn Neurosci. 2016 Jun;28(6):826-41. doi: 10.1162/jocn_a_00935. Epub 2016 Feb 4.
Recent evidence indicates that young adults frequently exhibit task-unrelated thoughts (TUTs) such as mind-wandering during episodic encoding tasks and that TUTs negatively impact subsequent memory. In the current study, we assessed age-related differences in the frequency and neural correlates of TUTs during a source memory encoding task, as well as age-related differences in the relationship between the neural correlates of TUTs and subsequent source forgetting effects (i.e., source misses). We found no age-related differences in frequency of TUTs during fMRI scanning. Moreover, TUT frequency at encoding was positively correlated with source misses at retrieval across age groups. In both age groups, brain regions including bilateral middle/superior frontal gyri and precuneus were activated to a greater extent during encoding for subsequent source misses versus source hits and during TUTs versus on-task episodes. Overall, our results reveal that, during a source memory encoding task in an fMRI environment, young and older adults exhibit a similar frequency of TUTs and that experiencing TUTs at encoding is associated with decreased retrieval performance. In addition, in both age groups, experiencing TUTs at encoding is associated with increased activation in some of the same regions that exhibit subsequent source forgetting effects.
近期证据表明，年轻人在情景编码任务中经常出现与任务无关的思维（TUTs），如走神，且TUTs会对后续记忆产生负面影响。在本研究中，我们评估了在源记忆编码任务期间TUTs的频率和神经关联的年龄相关差异，以及TUTs的神经关联与后续源遗忘效应（即源记忆错误）之间关系的年龄相关差异。我们发现在功能磁共振成像（fMRI）扫描期间，TUTs的频率没有年龄相关差异。此外，各年龄组中编码时的TUT频率与检索时的源记忆错误呈正相关。在两个年龄组中，与后续源记忆正确相比，在编码后续源记忆错误时以及与任务相关思维相比在TUTs期间，包括双侧中/额上回和楔前叶在内的脑区激活程度更高。总体而言，我们的结果表明，在fMRI环境下的源记忆编码任务中，年轻人和老年人表现出相似的TUTs频率，且编码时出现TUTs与检索表现下降有关。此外，在两个年龄组中，编码时出现TUTs与一些随后出现源遗忘效应的相同脑区激活增加有关。
