Ever-present in our environments, light entrains circadian rhythms over long timescales, influencing daily activity patterns, health and performance. Increasing evidence indicates that light also acts independently of the circadian system to directly impact physiology and behaviour, including cognition. Exposure to light stimulates brain areas involved in cognition and appears to improve a broad range of cognitive functions. However, the extent of these effects and their mechanisms are unknown. Intrinsically photosensitive retinal ganglion cells (ipRGCs) have emerged as the primary conduit through which light impacts non-image-forming behaviours and are a prime candidate for mediating the direct effects of light on cognition. Here, we review the current state of understanding of these effects in humans and mice, and the tools available to uncover circuit-level and photoreceptor-specific mechanisms. We also address current barriers to progress in this area. Current and future efforts to unravel the circuits through which light influences cognitive functions may inform the tailoring of lighting landscapes to optimize health and cognitive function.

光始终存在于我们的环境中，在很长一段时间内影响昼夜节律，影响日常活动模式、健康和表现。越来越多的证据表明，光的作用也独立于昼夜节律系统，直接影响生理和行为，包括认知。暴露在光线下会刺激涉及认知的大脑区域，似乎可以改善广泛的认知功能。然而，这些影响的程度及其机制尚不清楚。本质光敏视网膜神经节细胞（ipRGC）已成为光影响非图像形成行为的主要渠道，并且是介导光对认知的直接影响的主要候选者。在这里，我们回顾了对人类和小鼠这些影响的当前理解状态，以及可用于揭示电路水平和光感受器特异性机制的工具。我们还解决了当前该领域取得进展的障碍。当前和未来解开光影响认知功能的回路的努力可能会为照明景观的定制提供信息，以优化健康和认知功能。