Dopamine neurons, known for their role in reward and motivation during waking hours, also play a key part in strengthening motor memories while we sleep, according to new research from the University of Michigan. The study found that these neurons become active during nonrapid eye movement (NREM) sleep after individuals learn new skills.
The research was supported by grants from the National Institute of Neurological Disorders and Stroke and the National Institute of Mental Health. It focused on specific midbrain dopamine neurons that show increased activity only during NREM sleep following learning experiences. This activity is synchronized with memory-boosting sleep spindles and helps reinforce newly acquired motor skills, leading to improved performance when awake.
Study co-author Ada Eban-Rothschild, associate professor of psychology at the University of Michigan, said: “As alterations in dopamine signaling are associated with neurodegenerative diseases that also involve motor deficits and sleep disturbances, understanding these links could pave the way for improved therapeutics and advancements in human health.”
Eban-Rothschild emphasized the broader implications of the findings: “The findings highlight that sleep is an active biological period during which key neural circuits strengthen the skills and patterns we rely on every day.”
The study challenges previous assumptions about dopamine’s function by demonstrating its involvement not just in daytime learning but also in consolidating new abilities overnight. Researchers believe this insight could inform future therapies targeting both sleep quality and dopamine pathways to improve motor function and quality of life for people affected by neurological disorders.
The paper was published in Science Advances (DOI: 10.1126/sciadv.adw7427). Alongside Eban-Rothschild, authors include Bibi Alika Sulaman, Eric Chen, Aaron Crane, Sangjin Lee, and Gideon Rothschild.
