New York (PTI): Researchers have discovered that the human nervous system has its "unit burst generator" to control rhythmic movements such as walking, a breakthrough which they claim could soon lead to treatments for spinal cord injuries and Parkinson's disease.

By studying a simpler model of locomotion, in the medicinal leech, the researchers at University of Minnesota have found where these unit burst generators reside and that each nerve cord segment has a complete generator.

When a neuron fires, it sets off a chain reaction that gives rise to rhythmic movement. Once those circuits are turned on, the body essentially goes on autopilot. "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 behaviours like walking or crawling," lead researcher Karen Mesce said.

The researchers targeted the segmented leech for their study as they have fewer and larger neurons -- making them easier to analyse. Furthermore, and perhaps just as important, the study found that dopamine -- a common human hormone -- can turn each of these complete generator units on. Since dopamine regulates movements and activates those unit burst generators, the next step will be figuring out how dopamine makes individual neurons more or less active.

"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," the 'ScienceDaily' quoted Mesce as saying. The findings of the study have been published in the latest edition of the 'Journal of Neuroscience'.