VTA dopaminergic neuronal activity during NREM sleep is modulated by learning and facilitates motor memory consolidation

Memory consolidation enables animals to draw on past experiences to guide future behavior. This process involves system- and synaptic-level changes and predominantly occurs during sleep. While hippocampal-cortical circuits are well studied in this context, the contributions of other systems, including dopaminergic circuits-key players in learning-related processes-remain poorly understood. Ventral tegmental area dopaminergic (VTA^DA) neurons are active during sleep and suggested to participate in memory consolidation processes; however, causal evidence for this is lacking. Using calcium-dependent fiber photometry, electrophysiology, and chemogenetic and optogenetic manipulations across learning paradigms, we explore the functions of VTA^DA neuronal activity during sleep. We show that VTA^DA activity during nonrapid eye movement sleep is experience dependent, is enhanced by motor skill and associative learning, facilitates motor skill memory consolidation, and exhibits a motor learning-dependent increase in temporal coordination with cortical spindle oscillations. Our findings uncover a previously unidentified function for VTA^DA neurons in consolidating memories during sleep, advancing understanding of this central neuromodulator's functions in regulating fundamental biological processes.