D2.4 LIGHTCAP Integrative deliverable - Mechanisms

In this integrative report, we focus on the mechanisms studied in the LIGHTCAP project and the knowledge gained, or yet to be learned from the remaining analyses. Many projects are still ongoing, meaning that in most case only preliminary conclusions can be drawn at this stage. For further details and references, the reader is referred to the published and forthcoming manuscripts of the individual ESRs. The purpose of this deliverable is merely serves to outline at a high-level the directions and interrelationships of the numerous studies – both completed and ongoing – in LIGHTCAP.Following a presentation of the insights gained on the biological mechanisms of the non-image forming (NIF) impact of light, we present sources of modulation or variation of these mechanisms arising from i) biological factors and interaction between biological factors – ageing, disease, stress, arousal – and ii) light characteristics. We end the report with a description of what we consider to be the most urgent knowledge gaps about the mechanisms of action of light that need to be addressed in the future.