Linked Sources of Neural Noise Contribute to Age-related Cognitive Decline.
Linked Sources of Neural Noise Contribute to Age-related Cognitive Decline.
复制标题
神经噪声的相关来源会导致与年龄相关的认知能力下降。
DOI：
10.1162/jocn_a_01584
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发表时间：
2020
影响因子：
3.2
通讯作者：
Voytek,Bradley
中科院分区：
文献类型：
--
作者：
Tran,TamT;Rolle,CamarinE;Gazzaley,Adam;Voytek,Bradley
健康的衰老与大脑中大量的结构变化有关。这些与年龄相关的身体变化伴随着各种神经活动的变异性增加，而这种变异性的增加，统称为“神经噪音”，被认为是导致与年龄相关的认知能力下降的原因。在这项研究中，我们研究了两种特定类型的神经噪声在衰老中的关系。我们记录了年轻（20-30岁）和老年（60-70岁）成年人执行空间视觉识别任务的头皮脑电图。首先，我们使用脑电功率谱的1/f样指数（一种假定的神经噪声标记）来评估衰老过程中基线向噪声状态的转移。接下来，我们检查了与年龄相关的视觉刺激处理一致性的下降。最后，我们研究了这两种与年龄相关的噪音标记在多大程度上是相关的，假设更大的基线噪音会增加刺激诱发反应的可变性。我们发现，老年人的视觉皮层基线噪声更高，老年人对视觉目标的振荡α (8-12 Hz)相反应的一致性也低于年轻人。至关重要的是，基线噪音水平最高的老年人也有最不一致的α相反应，而相反应更一致的年轻人则有更好的行为表现。这些结果建立了强直性神经噪声和衰老过程中刺激相关的神经变异性之间的联系。此外，他们认为，与年龄相关的基线噪音的滋补性增加可能会减少感觉处理，从而减少随后的认知表现。
Healthy aging is associated with a multitude of structural changes in the brain. These physical age-related changes are accompanied by increased variability in neural activity of all kinds, and this increased variability, collectively referred to as “neural noise,” is argued to contribute to age-related cognitive decline. In this study, we examine the relationship between two particular types of neural noise in aging. We recorded scalp EEG from younger (20–30 years old) and older (60–70 years old) adults performing a spatial visual discrimination task. First, we used the 1/f-like exponent of the EEG power spectrum, a putative marker of neural noise, to assess baseline shifts toward a noisier state in aging. Next, we examined age-related decreases in the trial-by-trial consistency of visual stimulus processing. Finally, we examined to what extent these two age-related noise markers are related, hypothesizing that greater baseline noise would increase the variability of stimulus-evoked responses. We found that visual cortical baseline noise was higher in older adults, and the consistency of older adults' oscillatory alpha (8–12 Hz) phase responses to visual targets was also lower than that of younger adults. Crucially, older adults with the highest levels of baseline noise also had the least consistent alpha phase responses, whereas younger adults with more consistent phase responses achieved better behavioral performance. These results establish a link between tonic neural noise and stimulus-associated neural variability in aging. Moreover, they suggest that tonic age-related increases in baseline noise might diminish sensory processing and, as a result, subsequent cognitive performance.