Spinal cord injury (SCI) has long been viewed as a disruption of motor pathways. However, a new Perspective published in Science Bulletin argues that SCI is fundamentally a systems-level disorder—one that breaks communication, desynchronizes physiological states, and impairs learning across the brain–body–environment loop.
The study introduces a new conceptual framework: recovery should not focus solely on reactivating muscles, but on rebuilding closed-loop dialogue between cortical intention, spinal circuits, and sensory feedback. Without this loop, even preserved neural pathways cannot support stable or adaptive function.
The authors identify three coupled deficits underlying SCI. First, communication loss prevents motor commands from reaching spinal networks and blocks sensory feedback from reshaping the brain. Second, state mismatch leaves spinal circuits viable but outside a functional excitability range. Third, learning failure limits the ability of residual circuits to consolidate experience into lasting recovery.
To address these challenges, the article outlines three complementary technological routes.
The first route, brain–spinal cord interfaces, reconnects cortical signals with spinal stimulation to re-engage locomotor circuits. Recent studies have demonstrated that such "digital bridges" can restore natural walking in individuals with paralysis.
The second route, brain–peripheral interfaces, bypasses the lesion by translating neural signals into functional electrical stimulation of muscles or nerves. This approach is particularly suited for restoring upper-limb and fine motor functions.
The third route, sensory afferent interfaces, restores tactile and proprioceptive feedback through neural stimulation, allowing movement to become more stable, natural, and less cognitively demanding.
Importantly, the authors propose a unifying framework—a "neuromodulation palette"—with three functional layers: state-setting, execution, and plasticity-biasing. Together, these layers form an adaptive therapy system that integrates multiple technologies into a coherent closed-loop architecture.
The article also highlights key challenges for clinical translation, including limited observability of neural states, biological variability, long-term material stability, and unresolved ethical issues such as data governance and patient agency.
To overcome these barriers, the authors propose a stepwise roadmap, from non-invasive neuromodulation and wearable systems to implantable high-fidelity interfaces, ultimately aiming to build scalable, home-based rehabilitation ecosystems.
By shifting the focus from isolated interventions to system-level reconnection, this work provides a new perspective on how brain–computer interfaces can transform recovery after spinal cord injury.
