Pinal Diego, Zurrón Montserrat, Díaz Fernando
Applied Cognitive Neuroscience Laboratory, Department of Clinical Psychology and Psychobiology, Faculty of Psychology, Universidade de Santiago de Compostela, Galiza, Spain.
PLoS One. 2015 Nov 16;10(11):e0143117. doi: 10.1371/journal.pone.0143117. eCollection 2015.
Age-related decline in cognitive capacities has been attributed to a generalized slowing of processing speed and a reduction in working memory (WM) capacity. Nevertheless, it is unclear how age affects visuospatial WM recognition and its underlying brain electrical activity. Whether age modulates the effects of memory load or information maintenance duration, which determine the limits of WM, remains also elusive. In this exploratory study, performance in a delayed match to sample task declined with age, particularly in conditions with high memory load. Event related potentials analysis revealed longer N2 and P300 latencies in old than in young adults during WM recognition, which may reflect slowing of stimulus evaluation and classification processes, respectively. Although there were no differences between groups in N2 or P300 amplitudes, the latter was more homogeneously distributed in old than in young adults, which may indicate an age-related increased reliance in frontal vs parietal resources during WM recognition. This was further supported by an age-related reduced posterior cingulate activation and increased superior frontal gyrus activation revealed through standardized low resolution electromagnetic tomography. Memory load and maintenance duration effects on brain activity were similar in both age groups. These behavioral and electrophysiological results add evidence in support of age-related decline in WM recognition theories, with a slowing of processing speed that may be limited to stimulus evaluation and categorization processes--with no effects on perceptual processes--and a posterior to anterior shift in the recruitment of neural resources.
认知能力的年龄相关性衰退被归因于处理速度的普遍减慢和工作记忆（WM）容量的减少。然而，目前尚不清楚年龄如何影响视觉空间工作记忆识别及其潜在的脑电活动。年龄是否会调节记忆负荷或信息维持时长的影响（这两者决定了工作记忆的极限）也尚不明确。在这项探索性研究中，延迟样本匹配任务的表现随年龄增长而下降，尤其是在高记忆负荷条件下。事件相关电位分析显示，在工作记忆识别过程中，老年人的N2和P300潜伏期比年轻人更长，这可能分别反映了刺激评估和分类过程的减慢。尽管两组之间在N2或P300波幅上没有差异，但P300波幅在老年人中比在年轻人中分布更均匀，这可能表明在工作记忆识别过程中，与年龄相关的对额叶与顶叶资源的依赖增加。标准化低分辨率电磁断层扫描显示，后扣带回激活随年龄增长而减少，额上回激活随年龄增长而增加，这进一步支持了上述观点。两个年龄组中，记忆负荷和维持时长对大脑活动的影响相似。这些行为学和电生理学结果为支持工作记忆识别理论中的年龄相关性衰退提供了证据，即处理速度减慢可能仅限于刺激评估和分类过程（对感知过程无影响），以及神经资源募集从后向前的转移。
