Daneault Véronique, Dumont Marie, Massé Éric, Forcier Pierre, Boré Arnaud, Lina Jean-Marc, Doyon Julien, Vandewalle Gilles, Carrier Julie
Functional Neuroimaging Unit, University of Montreal Geriatric Institute, Montreal, QC, Canada.
Center for Advanced Research in Sleep Medicine, CIUSSS-NÎM - Hôpital du Sacré-Cœur de Montréal, Montreal, QC, Canada.
Front Physiol. 2018 Nov 6;9:1557. doi: 10.3389/fphys.2018.01557. eCollection 2018.
Beyond its essential visual role, light, and particularly blue light, has numerous non-visual effects, including stimulating cognitive functions and alertness. Non-visual effects of light may decrease with aging and contribute to cognitive and sleepiness complaints in aging. However, both the brain and the eye profoundly change in aging. Whether the stimulating effects light on cognitive brain functions varies in aging and how ocular changes may be involved is not established. We compared the impact of blue and orange lights on non-visual cognitive brain activity in younger (23.6 ± 2.5 years), and older individuals with their natural lenses (NL; 66.7 ± 5.1 years) or with intraocular lens (IOL) replacement following cataract surgery (69.6 ± 4.9 years). Analyses reveal that blue light modulates executive brain responses in both young and older individuals. Light effects were, however, stronger in young individuals including in the hippocampus and frontal and cingular cortices. Light effects did not significantly differ between older-IOL and older-NL while regression analyses indicated that differential brain engagement was not underlying age-related differences in light effects. These findings show that, although its impact decreases, light can stimulate cognitive brain activity in aging. Since lens replacement did not affect light impact, the brain seems to adapt to the progressive decrease in retinal light exposure in aging.
除了其基本的视觉作用外，光，尤其是蓝光，还具有许多非视觉效应，包括刺激认知功能和警觉性。光的非视觉效应可能会随着年龄增长而减弱，并导致老年人出现认知和困倦方面的问题。然而，大脑和眼睛在衰老过程中都会发生深刻变化。光对大脑认知功能的刺激作用在衰老过程中是否会有所不同，以及眼部变化可能如何参与其中，目前尚不清楚。我们比较了蓝光和橙光对年轻（23.6±2.5岁）以及老年个体非视觉认知脑活动的影响，老年个体分为保留自然晶状体（NL；66.7±5.1岁）和白内障手术后植入人工晶状体（IOL；69.6±4.9岁）两组。分析表明，蓝光可调节年轻和老年个体的大脑执行反应。然而，光效应在年轻个体中更强，包括在海马体、额叶和扣带回皮质。老年IOL组和老年NL组的光效应没有显著差异，而回归分析表明，大脑参与度的差异并不是光效应与年龄相关差异的基础。这些发现表明，尽管其影响会减弱，但光仍能刺激老年人的大脑认知活动。由于晶状体置换并不影响光的作用，大脑似乎适应了衰老过程中视网膜光暴露的逐渐减少。
