Georgia Institute of Technology, Atlanta, GA, USA.
Georgia Institute of Technology, Atlanta, GA, USA.
Neuropsychologia. 2020 Feb 17;138:107357. doi: 10.1016/j.neuropsychologia.2020.107357. Epub 2020 Jan 23.
Top-down modulation underlies our ability to focus attention on task-relevant stimuli and ignore irrelevant distractions. Although age-related differences in neural correlates of top-down modulation have been investigated in multiple studies using variety of tasks (Gazzaley et al., 2005; Störmer et al., 2013), the effect of age on top-down modulation in a multiple identity tracking (MIT) task is still unknown. Thus, we investigated age-related differences in the MIT task by employing event-related potentials (ERPs). Participants tracked ten uniquely colored disks, two of which were randomly designated as targets at the beginning of each trial; the targets moved among four stationary distractors (serving as ERP baseline) and four moving distractors. Each type of stimulus was probed during the trial to capture differential patterns of brain activation. Tracking performance was similar across age groups. ERP data showed that younger adults performed the MIT task by enhancing the unique identities associated with targets relative to distractors through feature-based tracking. Older adults showed a pattern of distractor suppression engaging both location- and feature-based tracking strategies. Thus, our findings suggest that compared to younger adults, older adults engage greater levels of neural activity to achieve the same level of performance. These findings are discussed in light of theories of cognitive aging.
自上而下的调节是我们专注于任务相关刺激、忽略不相关干扰的能力基础。尽管已有多项研究采用多种任务（Gazzaley 等人，2005；Störmer 等人，2013）调查了年龄相关的自上而下调节的神经相关性差异，但在多项身份跟踪（MIT）任务中年龄对自上而下调节的影响仍不清楚。因此，我们通过事件相关电位（ERP）研究了 MIT 任务中的年龄相关差异。参与者跟踪十个独特颜色的圆盘，其中两个在每个试验开始时被随机指定为目标；目标在四个静止的干扰物（作为 ERP 基线）和四个移动的干扰物之间移动。在试验期间探测每种类型的刺激以捕捉大脑激活的不同模式。跟踪性能在不同年龄组之间相似。ERP 数据显示，年轻成年人通过基于特征的跟踪增强与目标相关联的独特身份来执行 MIT 任务，而相对于干扰物。老年成年人表现出抑制干扰物的模式，同时涉及基于位置和基于特征的跟踪策略。因此，我们的发现表明，与年轻成年人相比，老年成年人需要更高水平的神经活动才能达到相同的表现水平。这些发现是根据认知老化理论讨论的。
