Diaz Michele T, Johnson Micah A, Burke Deborah M, Truong Trong-Kha, Madden David J
Department of Psychology, Pennsylvania State University, University Park, PA, 16803, USA.
Department of Psychology, University of California, Los Angeles, Los Angeles, CA, USA.
Cogn Affect Behav Neurosci. 2019 Aug;19(4):829-844. doi: 10.3758/s13415-018-00671-2.
As we age we have increasing difficulty with phonological aspects of language production. Yet semantic processes are largely stable across the life span. This suggests a fundamental difference in the cognitive and potentially neural architecture supporting these systems. Moreover, language processes such as these interact with other cognitive processes that also show age-related decline, such as executive function and inhibition. The present study examined phonological and semantic processes in the presence of task-irrelevant information to examine the influence of such material on language production. Older and younger adults made phonological and semantic decisions about pictures in the presence of either phonologically or semantically related words, which were unrelated to the task. FMRI activation during the semantic condition showed that all adults engaged typical left-hemisphere language regions, and that this activation was positively correlated with efficiency across all adults. In contrast, the phonological condition elicited activation in bilateral precuneus and cingulate, with no clear brain-behavior relationship. Similarly, older adults exhibited greater activation than younger adults in several regions that were unrelated to behavioral performance. Our results suggest that as we age, brain-behavior relations decline, and there is an increased reliance on both language-specific and domain-general brain regions that are seen most prominently during phonological processing. In contrast, the core semantic system continues to be engaged throughout the life span, even in the presence of task-irrelevant information.
随着年龄的增长，我们在语言产生的语音方面会遇到越来越多的困难。然而，语义过程在整个生命周期中基本保持稳定。这表明支持这些系统的认知和潜在神经结构存在根本差异。此外，诸如此类的语言过程与其他也显示出与年龄相关衰退的认知过程相互作用，比如执行功能和抑制能力。本研究考察了在存在与任务无关信息的情况下的语音和语义过程，以检验此类材料对语言产生的影响。年长和年轻的成年人在出现与语音或语义相关但与任务无关的单词时，对图片做出语音和语义判断。语义条件下的功能磁共振成像激活显示，所有成年人都激活了典型的左半球语言区域，并且这种激活与所有成年人的效率呈正相关。相比之下，语音条件下在双侧楔前叶和扣带回引发了激活，但没有明确的脑行为关系。同样，年长成年人在几个与行为表现无关的区域比年轻成年人表现出更大的激活。我们的研究结果表明，随着年龄的增长，脑行为关系会衰退，并且在语音处理过程中最显著地表现出对特定语言和一般领域脑区的依赖增加。相比之下，核心语义系统在整个生命周期中持续发挥作用，即使在存在与任务无关信息的情况下也是如此。
