Circadian rhythms in neurodegenerative disorders

Endogenous biological clocks, orchestrated by the suprachiasmatic nucleus, time the circadian rhythms that synchronize physiological and behavioural functions in humans. The circadian system influences most physiological processes, including sleep, alertness and cognitive performance. Disruption of circadian homeostasis has deleterious effects on human health. Neurodegenerative disorders involve a wide range of symptoms, many of which exhibit diurnal variations in frequency and intensity. These disorders also disrupt circadian homeostasis, which in turn has negative effects on symptoms and quality of life. Emerging evidence points to a bidirectional relationship between circadian homeostasis and neurodegeneration, suggesting that circadian function might have an important role in the progression of neurodegenerative disorders. Therefore, the circadian system has become an attractive target for research and clinical care innovations. Studying circadian disruption in neurodegenerative disorders could expand our understanding of the pathophysiology of neurodegeneration and facilitate the development of novel, circadian-based interventions for these disabling disorders. In this Review, we discuss the alterations to the circadian system that occur in movement (Parkinson disease and Huntington disease) and cognitive (Alzheimer disease and frontotemporal dementia) neurodegenerative disorders and provide directions for future investigations in this field. In this Review, Nassan and Videnovic discuss the alterations to the circadian system that occur in neurodegenerative disorders and highlight future directions for research in the field, including opportunities for the development of circadian-based therapeutic interventions.

Automated summary

The circadian system governs physiological processes like sleep, alertness, and cognition, and disruptions in circadian homeostasis can have detrimental effects on human health, especially in neurodegenerative disorders. There is a bidirectional relationship between circadian function and neurodegeneration, highlighting the importance of studying circadian disruption in these disorders. Research in this field could lead to novel circadian-based therapeutic interventions for disabling conditions like Parkinson's, Alzheimer's, and other neurodegenerative diseases.