The locus coeruleus, a key regulator of human sleep
Despite decades of research, sleep remains largely mysterious. While animal studies have highlighted the role of subcortical structures in its regulation, human data remain scarce. A team from ULiège (GIGA-CRC-Human Imaging), led by Nasrin Mortazavi and Gilles Vandewalle, has investigated the involvement of the locus coeruleus - a tiny brainstem structure - the size of a grain of rice - in sleep dynamics.
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icknamed the “blue dot” because of its iron-rich pigmentation, the locus coeruleus is the brain's only source of noradrenaline, a neuromodulator essential for wakefulness and vigilance. Its activity must decrease to allow sleep onset, and fluctuate throughout the night to regulate the different phases of sleep. Using high-resolution 7 Tesla MRI imaging, the researchers observed that “the balance of locus coeruleus activity during wakefulness is essential for the proper expression of REM sleep”, explains Nasrin Mortazavi.
These results suggest that, as in rodents, the locus coeruleus plays an active role in regulating human sleep. “A better understanding of this mechanism could pave the way for targeted interventions to improve sleep quality, particularly in patients suffering from neurodegenerative disorders”, emphasizes Gilles Vandewalle. As this structure is one of the first to be affected by diseases such as Alzheimer's or Parkinson's, “sleep disorders could thus be an early sign of the disease”, adds Nasrin Mortazavi.
Scientific reference
Mortazavi N, Talwar P, Koshmanova E, Sharifpour R, Beckers E, Berger A, Campbell I, Paparella I, Balda F, Dardour Hamzaoui I, Berthomier C, Bastin C, Phillips C, Maquet P, Collette F, Zubkov M, Lamalle L, Vandewalle G., REM sleep quality is associated with balanced tonic activity of the locus coeruleus during wakefulness. , J Biomed Sci. 2025 Mar 11;32(1):35. doi: 10.1186/s12929-025-01127-9.
