<b>Circadian Rhythm Enhancing Brain Synchronization and Cognition</b> Cognition is impaired in many neuropsychiatric disorders and the quality of life is severely affected. A key mechanism for sculpting communication patterns between large scale brain networks that underpin cognition and its breakdown in neuropsychiatric disorders is synchronous electrophysiological rhythms. According to a study, light has a wide range of effects on the synchronization of circadian rhythms with the external environment and it is found that light influences the urinary excretion of melatonin and controls sleep. Autonomic and neuroendocrine responses such as feedback regulation and the involvement of the immune system have also been shown to influence the circadian rhythm. There have been major advances in our understanding of the retinal photoreceptors mediating these non image forming light responses over the last two decades, as well as the neural pathways and molecular mechanisms that generate and energize circadian rhythms in the phase of the light dark LD cycle. Our understanding of the mechanisms by which lighting impacts cognitive processes, on the other hand, is more misleading. Light s effect on different cognitive processes is complex. Indirect effects may also arise due to disrupted circadian rhythm, in addition to the direct effects of light on consciousness. In studies that rely on various cognitive and sensory processes, different assays have been used, which can also contribute to variable outcomes. The physiological basis of these responses and the influence of various lighting environments on cognitive processes are summarized here, taking into account their effects on circadian rhythms, sleep and arousal. cognition, circadian disruption, sleep disturbance, neuropsychiatric disorders 315-322 Issue-6 Volume-5 Uthirakumar Devaraj | Elumalai Balamurugan