Methqal Ikram, Provost Jean-Sebastien, Wilson Maximiliano A, Monchi Oury, Amiri Mahnoush, Pinsard Basile, Ansado Jennyfer, Joanette Yves
Laboratory of Communication and Aging, Institut Universitaire de Gériatrie de Montréal, MontrealQC, Canada.
Faculty of Medicine, University of Montreal, MontrealQC, Canada.
Front Aging Neurosci. 2017 Aug 10;9:265. doi: 10.3389/fnagi.2017.00265. eCollection 2017.
Growing evidence from the neuroscience of aging suggests that executive function plays a pivotal role in maintaining semantic processing performance. However, the presumed age-related activation changes that sustain executive semantic processing remain poorly understood. The aim of this study was to explore the executive aspects of semantic processing during a word-matching task with regard to age-related neuro-functional reorganization, as well as to identify factors that influence executive control profiles. Twenty younger and 20 older participants underwent fMRI scanning. The experimental task was based on word-matching, wherein visual feedback was used to instruct participants to either maintain or switch a semantic-matching rule. Response time and correct responses were assessed for each group. A battery of cognitive tests was administrated to all participants and the older group was divided into two subgroups based on their cognitive control profiles. Even though the percentage of correct responses was equivalent in the task performance between both groups and within the older groups, neuro-functional activation differed in frontoparietal regions with regards to age and cognitive control profiles. A correlation between behavioral measures (correct responses and response times) and brain signal changes was found in the left inferior parietal region in older participants. Results indicate that the shift in age-related activation from frontal to parietal regions can be viewed as another form of neuro-functional reorganization. The greater reliance on inferior parietal regions in the older compared to the younger group suggests that the executive control system is still efficient and sustains semantic processing in the healthy aging brain. Additionally, cognitive control profiles underlie executive ability differences in healthy aging appear to be associated with specific neuro-functional reorganization throughout frontal and parietal regions. These findings demonstrate that changes in neural support for executive semantic processing during a word-matching task are not only influenced by age, but also by cognitive control profile.
来自衰老神经科学的越来越多的证据表明，执行功能在维持语义处理能力方面起着关键作用。然而，维持执行语义处理的与年龄相关的假定激活变化仍知之甚少。本研究的目的是在单词匹配任务中，探讨与年龄相关的神经功能重组方面的语义处理执行情况，并确定影响执行控制概况的因素。20名年轻参与者和20名年长参与者接受了功能磁共振成像扫描。实验任务基于单词匹配，其中视觉反馈用于指导参与者维持或切换语义匹配规则。评估了每组的反应时间和正确反应。对所有参与者进行了一系列认知测试，并根据年长组的认知控制概况将其分为两个亚组。尽管两组之间以及年长组内任务表现中的正确反应百分比相当，但额叶顶叶区域的神经功能激活在年龄和认知控制概况方面存在差异。在年长参与者的左下顶叶区域发现了行为测量（正确反应和反应时间）与脑信号变化之间的相关性。结果表明，与年龄相关的激活从额叶向顶叶区域的转变可被视为神经功能重组的另一种形式。与年轻组相比，年长组对下顶叶区域的更大依赖表明，执行控制系统在健康衰老大脑中仍然有效并维持语义处理。此外，健康衰老中执行能力差异背后的认知控制概况似乎与额叶和顶叶区域的特定神经功能重组有关。这些发现表明，单词匹配任务中执行语义处理的神经支持变化不仅受年龄影响，还受认知控制概况影响。
