iScience. 2025 Feb 7;28(3):111971. doi: 10.1016/j.isci.2025.111971. eCollection 2025 Mar 21.
ABSTRACT
Spinal circuits generate locomotor rhythms, but the mechanisms behind episodic locomotor behaviors remain unclear. This study investigated dopamine-induced episodic rhythms in isolated neonatal mouse spinal cords to understand these mechanisms. The episodic rhythms were generally synchronous and propagated rostro-caudally, although occasional asynchrony was observed. Electrical stimulation of the L5 dorsal root entrained the episodic rhythms, suggesting afferent control and a distributed network. Even after transection or ventrolateral funiculus (VLF) lesions, episodic activity persisted in isolated thoracic or sacral segments, implying VLF-coupled networks. Rhythmicity was observed in VLF and dorsal root axons and was independent of cholinergic excitation via motoneurons, GABAA receptors, or dorsal inhibitory circuits. These findings suggest a flexibly coupled, distributed spinal interneuron network underlies episodic rhythmicity, providing a foundation for future investigations into how spinal circuits are modulated to produce diverse motor outputs.
PMID:40060907 | PMC:PMC11889695 | DOI:10.1016/j.isci.2025.111971
