health Paradigm Challenge

Stroke patients are learning to use their fingers again by tapping into 'backup' nerve pathways we thought were useless for fine movement.

March 27, 2026

Original Paper

Recovery of Dexterous Motor Control via Non-Monosynaptic Corticospinal Pathways

Sorensen, E.; Borda, L.; Ostrowski, J.; de Freitas, R. M.; Verma, N.; Fisher, L. E.; Wittenberg, G. F.; Gerszten, P.; Weber, D. J.; Pirondini, E.; Gorassini, M.; Krakauer, J. W.; Capogrosso, M.

medRxiv · 10.64898/2026.03.24.26348827

AI-generated illustration

The Takeaway

Standard neuroanatomy suggests that dexterity is only possible via direct 'high-speed' connections between the brain and spinal cord. This study reveals that the brain can bypass these damaged links and 'sculpt' indirect, messy reflex circuits to perform precise movements, fundamentally changing our understanding of how the motor system recovers.

From the abstract

Fine motor control of the human arm is assumed to depend on monosynaptic connections between the motor cortex and spinal motoneurons. We report that people with post-stroke hemiparesis could regain dexterous control using non-monosynaptic corticospinal tract (CST) projections during epidural cervical spinal cord stimulation (SCS). Participants in our pilot clinical study demonstrated the ability to improve strength, reaching smoothness, and fine force control of the arm and hand while receiving