In brightness, the pupil constricts, while in darkness, the pupil dilates; this is known as the pupillary light response (PLR). The PLR is driven by all photoreceptors: rods and cones, which contribute to image-forming vision, and intrinsically photosensitive retinal ganglion cells (ipRGCs), which mainly contribute to non-image-forming vision. Rods and cones cause immediate pupil constriction upon light exposure, whereas ipRGCs cause sustained constriction throughout light exposure. Recent studies have shown that covert attention modulated the initial PLR; however, it remains unclear whether the same holds for the sustained PLR. We tested this by leveraging ipRGCs’ responsiveness to blue light, causing the most prominent sustained constriction. While replicating previous studies by showing that pupils constricted more when either directly looking at, or covertly attending to, bright as compared to dim stimuli (with the same color), we also found that the pupil constricted more when directly looking at blue as compared to red stimuli (with the same luminosity). Crucially, however, in two high-powered studies (n = 60), we did not find any pupil-size difference when covertly attending to blue as compared to red stimuli. This suggests that ipRGC-mediated pupil constriction, and possibly non-image-forming vision more generally, is not modulated by covert attention.

中文翻译：

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通过 ipRGC 介导的瞳孔收缩测量的非成像视力不受隐性视觉注意的调节

在明亮的情况下，瞳孔收缩，在黑暗的情况下，瞳孔放大；这称为瞳孔光反应 (PLR)。 PLR 由所有感光细胞驱动：视杆细胞和视锥细胞，它们有助于形成图像视觉，以及本质上感光的视网膜神经节细胞 (ipRGC)，它们主要有助于非图像形成视觉。视杆细胞和视锥细胞在光照下引起瞳孔立即收缩，而 ipRGC 在光照过程中引起持续收缩。最近的研究表明，隐性注意力调节初始 PLR；然而，目前尚不清楚持续的 PLR 是否同样如此。我们通过利用 ipRGC 对蓝光的响应来测试这一点，导致最显着的持续收缩。虽然重复了之前的研究，表明与暗淡刺激（相同颜色）相比，直接观看或暗中注意明亮刺激时瞳孔收缩更多，但我们还发现，与直接观看蓝色刺激相比，瞳孔收缩更多红色刺激（具有相同的亮度）。然而，至关重要的是，在两项高性能研究 (n = 60) 中，我们在秘密关注蓝色刺激和红色刺激时没有发现任何瞳孔大小差异。这表明 ipRGC 介导的瞳孔收缩，以及更普遍的可能的非成像视觉，不受隐性注意力的调节。