Gait disturbance in individuals with spinal cord injury is attributed to interruption of descending pathways to spinal locomotor network, although neural circuits locate below and above the lesion remain most their function. An artificial neural connection that bridges supra-spinal centers and locomotor network in lumbar spinal cord beyond the lesion site might have potential to restore the functional loss. Here we show that an artificial neural connection that delivers the descending command associated with arm muscle activity can induce volitional walking-like behavior of paralysis legs in individuals with a complete spinal cord injury (SCI).
Two individuals with a complete SCI were participated in the present study. The lesion sites in two individuals were Th12 and Th3 respectively. According to neurological criteria and the ASIA classification, they were classified as complete SCI and ASIA A category with no motor and sensory function below the lesion site. The artificial neural connection was produced by a brain-computer interface that detects the activity pattern of hand muscle and to deliver hand muscle activity-dependent non-invasive magnetic stimuli over the lumbar spinal cord.
Walking behavior in paralysis legs could be induced via artificial neural connection. Individuals were able to control start/stop and step cycle of the behavior. This behavior was not seen while the artificial neural connection was terminated even when the subject continued hand muscle contraction.
These results suggest that the walking behavior in paralysis legs could be controlled volitionally via the artificial neural connection. This paradigm was useful to regain volitional walking in individuals with complete SCI.