Medicine: impulses despite paraplegia

Medicine: impulses despite paraplegia

Despite spinal cord injury, spinal cord sends impulses to legs

With paraplegia, the spinal cord sends impulses to the leg muscles despite the broken connection to the command center. The processes work similarly to the headless chicken that runs around in the yard. Researchers at the Center for Medical Physics and Biomedical Technology at MedUni Vienna recently discovered the activation patterns in the spinal cord that are responsible for walking. They published their results in the renowned journal “Brain”.

Nerve ligaments spinal cord activate muscles in the legs In people who have paraplegia, despite the lack of a connection between the spinal cord and the brain, electrical impulses from a stimulator can activate the leg muscles and trigger rhythmic movements. Nerve ligaments, so-called locomotion centers, are responsible for this. "Using statistical methods, we were able to identify a small number of basic patterns that are based on movement-related muscle activity in the legs and that control the periodic activation or inactivation of the muscles, which results in cyclical movements like walking," explains study author Simon Danner. "Similar to a modular system, the nerve network in the spinal cord flexibly combines these basic patterns depending on the movement requirements."

The brain stem forms the "command center", but the complex motor arousal patterns are generated by nerve networks in the spinal cord. Most vertebrates have such locomotive centers. The principle can be observed that the spinal cord also sends out impulses when the brain is no longer involved, for example in the headless chicken that runs around in the yard. "Even after loss of control by the brain, the spinal cord still sends out motor signals that are converted into running and wing movements," reports the MedUni in a communication on the study.

Paraplegics could benefit from knowledge of activation patterns for walking in the spinal cord. The researchers' findings should flow into rehabilitation medicine, among other things. This could benefit patients who are paraplegic after an accident by continuing to use the nerve associations that are not damaged through electrical stimuli. This could partially reactivate lost rhythmic movement possibilities.

Further studies will investigate how the nerve clusters have to be stimulated exactly. That depends, among other things, on the individual injury profile, reports the MedUni. To this end, the researchers developed a globally unique, non-invasive spinal cord stimulation method that works via surface electrodes that are attached to the skin. "This method allows simplified access to the nerve associations in the spinal cord below a spinal cord injury and can therefore be made available to paraplegics without special medical risks and stress," said Karen Minassian, senior author of the study. (ag)

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