Beckers Elise, Campbell Islay, Sharifpour Roya, Paparella Ilenia, Berger Alexandre, Aizpurua Jose Fermin Balda, Koshmanova Ekaterina, Mortazavi Nasrin, Talwar Puneet, Sherif Siya, Jacobs Heidi I L, Vandewalle Gilles
GIGA-Cyclotron Research Centre-In Vivo Imaging, University of Liège, Liège, Belgium.
Faculty of Health, Medicine and Life Sciences, School for Mental Health and Neuroscience, Alzheimer Centre Limburg, Maastricht University, Maastricht, the Netherlands.
J Sleep Res. 2024 Aug;33(4):e14085. doi: 10.1111/jsr.14085. Epub 2023 Oct 30.
Light triggers numerous non-image-forming, or non-visual, biological effects. The brain correlates of these non-image-forming effects have been investigated, notably using magnetic resonance imaging and short light exposures varying in irradiance and spectral quality. However, it is not clear whether non-image-forming responses estimation may be biased by having light in sequential blocks, for example, through a potential carryover effect of one light onto the next. We reasoned that pupil light reflex was an easy readout of one of the non-image-forming effects of light that could be used to address this issue. We characterised the sustained pupil light reflex in 13-16 healthy young individuals under short light exposures during three distinct cognitive processes (executive, emotional and attentional). Light conditions pseudo-randomly alternated between monochromatic orange light (0.16 melanopic equivalent daylight illuminance lux) and polychromatic blue-enriched white light of three different levels (37, 92, 190 melanopic equivalent daylight illuminance lux). As expected, higher melanopic irradiance was associated with larger sustained pupil light reflex in each cognitive domain. This result was stable over the light sequence under higher melanopic irradiance levels compared with lower ones. Exploratory frequency-domain analyses further revealed that sustained pupil light reflex was more variable under lower melanopic irradiance levels. Importantly, sustained pupil light reflex varied across tasks independently of the light condition, pointing to a potential impact of light history and/or cognitive context on sustained pupil light reflex. Together, our results emphasise that the distinct contribution and adaptation of the different retinal photoreceptors influence the non-image-forming effects of light and therefore potentially their brain correlates.
光引发众多非成像或非视觉的生物学效应。人们已对这些非成像效应的大脑关联进行了研究，特别是使用磁共振成像以及不同辐照度和光谱质量的短时光照。然而，尚不清楚非成像反应的估计是否会因光照呈连续块状而产生偏差，例如，一种光照对下一种光照可能存在的残留效应。我们推断瞳孔光反射是一种易于读取的光的非成像效应之一，可用于解决这一问题。我们对13至16名健康年轻个体在三种不同认知过程（执行、情绪和注意力）中的短时光照下的持续性瞳孔光反射进行了表征。光照条件在单色橙色光（0.16黑素视亮度等效日光照度勒克斯）和三种不同水平（37、92、190黑素视亮度等效日光照度勒克斯）的多色富蓝光白光之间伪随机交替。正如预期的那样，在每个认知领域中，较高的黑素视辐照度与较大的持续性瞳孔光反射相关。与较低黑素视辐照度水平相比，该结果在较高黑素视辐照度水平下的光照序列中更为稳定。探索性频域分析进一步表明，在较低黑素视辐照度水平下，持续性瞳孔光反射的变异性更大。重要的是，持续性瞳孔光反射在不同任务中有所不同，与光照条件无关，这表明光照历史和/或认知背景对持续性瞳孔光反射可能有潜在影响。总之，我们的结果强调不同视网膜光感受器的独特贡献和适应性会影响光的非成像效应，进而可能影响其大脑关联。
