Brain Dynamics and Cognition Team, Lyon Neuroscience Research Center, CRNL, INSERM U1028, CNRS UMR5292, University of Lyon 1, Université de Lyon, Lyon, France.
Centre for Cognitive Neuroimaging, Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, Nijmegen, The Netherlands.
PLoS One. 2020 Mar 12;15(3):e0229334. doi: 10.1371/journal.pone.0229334. eCollection 2020.
Attention operates through top-down (TD) and bottom-up (BU) mechanisms. Recently, it has been shown that slow (alpha) frequencies index facilitatory and suppressive mechanisms of TD attention and faster (gamma) frequencies signal BU attentional capture. Ageing is characterized by increased behavioral distractibility, resulting from either a reduced efficiency of TD attention or an enhanced triggering of BU attention. However, only few studies have investigated the impact of ageing upon the oscillatory activities involved in TD and BU attention. MEG data were collected from 14 elderly and 14 matched young healthy human participants while performing the Competitive Attention Task. Elderly participants displayed (1) exacerbated behavioral distractibility, (2) altered TD suppressive mechanisms, indexed by a reduced alpha synchronization in task-irrelevant regions, (3) less prominent alpha peak-frequency differences between cortical regions, (4) a similar BU system activation indexed by gamma activity, and (5) a reduced activation of lateral prefrontal inhibitory control regions. These results show that the ageing-related increased distractibility is of TD origin.
注意通过自上而下（TD）和自下而上（BU）的机制发挥作用。最近的研究表明，较慢的（alpha）频率指数促进 TD 注意的机制和更快的（gamma）频率信号 BU 注意力捕获。随着年龄的增长，行为分心的情况会增加，这可能是由于 TD 注意力的效率降低，或者是 BU 注意力的触发增强。然而，只有少数研究调查了衰老对涉及 TD 和 BU 注意力的振荡活动的影响。MEG 数据是从 14 名老年和 14 名匹配的年轻健康人类参与者在执行竞争注意任务时收集的。老年参与者表现出（1）行为分心加剧，（2）TD 抑制机制改变，任务不相关区域的 alpha 同步减少，（3）皮质区域之间的 alpha 峰值频率差异较小，（4）gamma 活动指示的 BU 系统激活相似，以及（5）外侧前额叶抑制控制区域的激活减少。这些结果表明，与衰老相关的注意力分散增加是 TD 机制的结果。
