"Knowing which circuits are important and understanding how they control the essential aspects of walking should put us in a better position to design treatments or implants that restore or activate these pathways," said Martyn D. Goulding, Ph.D., a professor in the Molecular Neurobiology Laboratory.
The Salk research team ?led by Goulding?published their findings in the March 9, 2006 issue of the journal Nature. Joint lead authors were Simon Gosgnach, Ph.D. and Guillermo M. Lanuza, Ph.D. in Goulding's laboratory.
Whether fish or fowl, the muscle contractions that allow us to move generally have certain rhythmic properties. It has been known for some time that a central pattern generator (CPG) ?specialized groups of neurons in the spinal cord ?functions as the control and command center for these rhythmic movements. As such, the CPG lies at the heart of all locomotion. Remarkably, this circuitry functions without any input from the brain, which explains why headless chickens run away from the butcher's block.
"Although people have known about the CPG for a long time, they haven't been able to identify the nerve cells that are part of these circuits. Even at closer inspection, the spinal cord is just a jumbled mass of hundreds of thousands of neurons that all look the same," said Gosgnach.
The Salk team used genetic approaches to identify a subset of neurons, named V1 neurons, as being part of the CPG, and gene targeting methods to selectively disable them in order to observe what happens. "It allowed us to peer into this black box that is the centra