The researchers hope to help children with cerebral palsy and adults with spinal cord injuries by studying the emergence of walking behaviors in both human babies and infant animals.
The group is based at VU University, Amsterdam, Netherlands, and their work features at the Society for Experimental Biology (SEB) Annual Meeting, Brighton, United Kingdom, 4-7 July 2016.
Dr. Nadia Dominici, who heads the group at VU University's Faculty of Behavioral and Movement Sciences, explains what they do:
"We look at the emergence of walking behaviors in both human babies and infant animals, as they develop."
Even before they stand up, babies have an idea of what to do to start walking. If an infant is held over the floor, it will often attempt to put one foot in front of the other, clearly indicating an instinct for walking.
All that is needed is time for the right brain circuits to mature, and one day, the baby becomes a toddler.
Dr. Dominici and colleagues say this "primitive stepping reflex" is the foundation on which babies build their independent walking movement.
They have discovered that walking and similar movements are the result of small groups of muscles coming together in a flexible way to simplify the control of locomotion - they call these groups the "walking" or "locomotion primitives."
Species may share ancestral neural network for walking
"We found that human babies are born with just two walking primitives," Dr. Dominici explains, "the first directs the legs to bend and extend, the second commands the baby's legs to alternate - left, right, left, right - in order to move forward."
"To walk independently," she adds, "babies learn two more primitives, which we believe handle balance control, step timing, and weight shifting."
After studying many different animals, the team found that the primitives were remarkably alike, despite all the differences in body structure and evolution.
Dr. Dominici says, "locomotion in several animal species could start from common primitives, maybe even stemming from a common ancestral neural network."
The researchers believe their findings could help patients with walking disabilities improve their mobility. They have already shown it is possible to use neural primitives to improve walking in injured rats.
Cerebral palsy is a disorder caused by damage to the developing brain that affects movement, muscle tone, and posture. Children with cerebral palsy may have a reduced range of movement and some may not be able to walk properly.
The team is now working out how to apply their approach to children with cerebral palsy and adults with spinal cord injuries.
"We are showing that humans and other terrestrial animals learn how to walk in surprisingly similar ways."
Dr. Nadia Dominici