Zhuang Jie, Johnson Micah A, Madden David J, Burke Deborah M, Diaz Michele T
Brain Imaging and Analysis Center, Duke University School of Medicine, United States.
Brain Imaging and Analysis Center, Duke University School of Medicine, United States; Department of Psychiatry and Behavioral Sciences, Duke University School of Medicine, United States.
Neuropsychologia. 2016 Dec;93(Pt A):189-199. doi: 10.1016/j.neuropsychologia.2016.10.016. Epub 2016 Oct 29.
Receptive language (e.g., reading) is largely preserved in the aging brain, and semantic processes in particular may continue to develop throughout the lifespan. We investigated the neural underpinnings of phonological and semantic retrieval in older and younger adults during receptive language tasks (rhyme and semantic similarity judgments). In particular, we were interested in the role of competition on language retrieval and varied the similarities between a cue, target, and distractor that were hypothesized to affect the mental process of competition. Behaviorally, all participants responded faster and more accurately during the rhyme task compared to the semantic task. Moreover, older adults demonstrated higher response accuracy than younger adults during the semantic task. Although there were no overall age-related differences in the neuroimaging results, an Age×Task interaction was found in left inferior frontal gyrus (IFG), with older adults producing greater activation than younger adults during the semantic condition. These results suggest that at lower levels of task difficulty, older and younger adults engaged similar neural networks that benefited behavioral performance. As task difficulty increased during the semantic task, older adults relied more heavily on largely left hemisphere language regions, as well as regions involved in perception and internal monitoring. Our results are consistent with the stability of language comprehension across the adult lifespan and illustrate how the preservation of semantic representations with aging may influence performance under conditions of increased task difficulty.
接受性语言（如阅读）在衰老的大脑中基本得以保留，尤其是语义加工过程可能在整个生命周期中持续发展。我们研究了老年人和年轻人在接受性语言任务（押韵和语义相似性判断）中语音和语义提取的神经基础。具体而言，我们关注竞争对语言提取的作用，并改变了线索、目标和干扰项之间的相似性，这些因素被认为会影响竞争的心理过程。行为学上，与语义任务相比，所有参与者在押韵任务中的反应更快且更准确。此外，在语义任务中，老年人的反应准确率高于年轻人。尽管神经影像学结果没有显示出与年龄相关的总体差异，但在左侧额下回（IFG）发现了年龄×任务交互作用，在语义条件下，老年人比年轻人激活程度更高。这些结果表明，在较低任务难度水平下，老年人和年轻人使用相似的神经网络，这有利于行为表现。随着语义任务难度增加，老年人更多地依赖于主要位于左半球的语言区域，以及参与感知和内部监测的区域。我们的结果与成年期语言理解的稳定性一致，并说明了随着年龄增长语义表征的保留如何在任务难度增加的情况下影响表现。
