The whole vertebral column in profile along the curves it actually has, every bone drawn with its body, its arch around the canal and its spinous process, labelled C1 to the coccyx, with thirty-one pairs of nerve roots leaving it, the cord ending in a cone and the cauda equina below. Beside it, a ring of the three coverings — dura, arachnoid and pia — with the fluid space between them.
Cervical regionEight segments, C1–C8. The nerves to the diaphragm, the shoulders and the arms leave from here.
Lumbar regionFive segments, L1–L5. The nerves to the hips and legs leave from here.
Ventral hornThe front part of the butterfly. The motor neurons that drive muscles directly sit here.
Ventral rootThe bundle of fibres leaving the cord in front, carrying motor commands out to the muscles.
Spinal nerveThe dorsal and ventral roots join and leave the spine as one nerve carrying both sensory and motor fibres. There are 31 pairs.
Corticospinal tractA descending path from the motor cortex to the motor neurons. It carries voluntary movement and crosses to the other side in the brainstem.
Motor signsWeakness, loss of voluntary movement, a change in tone. What exactly, and where, depends on the level and the completeness.
Spinal shockA temporary state right after an injury in which reflexes below the level disappear and muscles go flaccid. Reflexes usually return over time. It is a state of the reflexes, not of the circulation.
Identifiers
DOI: 10.1038/s41586-023-06094-5
PubMed ID: 37225984
PMCID: PMC10232367
Claims this paper bears on
Supports — Users of a brain–spine interface report natural volitional control over leg movements after spinal cord injury.
Supports — Neurorehabilitation supported by a brain–spine interface improves neurological recovery after spinal cord injury, including walking ability when the stimulation is switched off.
Supports — A brain–spine interface that links cortical signals to epidural electrical stimulation of the lumbosacral spinal cord restores standing and walking ability after spinal cord injury.
Contradicts — A fully implanted brain–spine interface maintains reliable calibration and performance over long-term independent use after spinal cord injury.
A highly reliable BSI is calibrated within a few minutes. This reliability has remained stable over one year, including during independent use at home.
The participant reports that the BSI enables natural control over the movements of his legs to stand, walk, climb stairs and even traverse complex terrains.
Here, we restored this communication with a digital bridge between the brain and spinal cord that enabled an individual with chronic tetraplegia to stand and walk naturally in community settings.