The researchers at University of Minnesota have made a path breaking discovery that may throw light upon how the spinal cord controls walking. This may pave the way for developing treatments for diseases such as Parkinson's disease and spinal cord injuries.
Led by Joshua Puhl, Ph.D., and Karen Mesce, Ph.D., in the Departments of Entomology and Neuroscience, the study has found a possibility that the human nervous system, within each segment or region of spinal cord, may have its own "unit burst generator" to control rhythmic movements such as walking.
The researchers chose to study a simpler model of locomotion in the medicinal leech, and this uncovered the residing spots of these unit burst generators and it also showed that each nerve cord segment has a complete generator.
It was discovered that a neuron triggers to set off a chain reaction that gives rise to rhythmic movement and the moment those circuits are turned on, the body essentially goes on autopilot.
The researchers mainly focused on the segmented leech for study as they have fewer and larger neurons, making them easier to study. "For most of us, we can chew gum and walk at the same time. We do not have to remind ourselves to place the right leg out first, bring it back and do the same for the other leg. So how does the nervous system control rhythmic behaviors like walking or crawling," said Mesce.
The study also discovered that dopamine, a common human hormone, can turn each of these complete generator units on. "Because dopamine affects movement in many different animals, including humans, our studies may help to identify treatments for Parkinson's patients and those with spinal cord injury," said Mesce.
The study was published online in the Journal of Neuroscience.