Spinal Advance Gets Rats Running (via BBC News)
US, Russian and Swiss scientists used drugs and electrical stimulation to train the animals, whose spinal cords had been cut, to run on a treadmill. Their movement was “almost indistinguishable” from normal steps, they said. But the report, published in Nature Neuroscience, stressed the movement was not directly controlled by the mind….
The earlier discovery that these patterns of motor signals may be partly governed in the spinal cord itself is the key to the latest research. It is suggested that nerve circuits called “central pattern generators” may exist even at the base of the cord, underneath the point of the injury.
The teams from the University of Zurich and the University of California at Los Angeles believe they have found a way to harness this.
They used drugs which stimulate unused motor nerve circuitry, coupled with electrical stimulation, with the aim of activating these central pattern generators and producing a stepping action in the legs below. The rats, despite having no connection between their brains and their legs, were able to carry their own weight at walking, and even running pace, on a treadmill, with virtually no differences between their gait and the running style of a healthy rat….
Snakes Use Friction And Redistribution Of Their Weight To Slither On Flat Terrain
Snakes use both friction generated by their scales and redistribution of their weight to slither along flat surfaces, researchers at New York University and the Georgia Institute of Technology have found. Their findings, which appear in the latest issue of the Proceedings of the National Academy of Sciences, run counter to previous studies that have shown snakes move by pushing laterally against rocks and branches….
To explore this matter, the researchers first developed a theoretical model of a snake’s movement. The model determined the speed of a snake’s center of mass as a function of the speed and size of its body waves, taking into account the laws of friction and the scales’ frictional anisotropy. The model suggested that a snake’s motion arises by the interaction of surface friction and its internal body forces.
To confirm movement as predicted by the model, the researchers then measured the sliding resistance of snake scales and monitored the movement of snakes through a series of experiments on flat and inclined surfaces. They employed video and time-lapse photography to gauge their movements.
The results showed a close relationship between what the model predicted and the snakes’ actual movements. The theoretical predictions of the model were generally consistent with the snakes’ actual body speeds on both flat and inclined surfaces…. (more @ ScienceDaily)
