Control of movement: Spinal cord motor circuits

Perhaps the most fundamental thing we do is move - whether in speaking, in playing the piano or dancing, or lifting weights. Large parts of our central nervous systems are wired to ensure that we move appropriately for the task at hand. But how are we wired to move? There are multiple brain circuits involved. Some do the planning, make the decision, and select the appropriate movement. These circuits tell "command" neurons in the brain stem which movement to perform, and these neurons inform our organising circuits in the spinal cord that in turn tell our motor neurons how strongly to activate muscles. In this application (a renewal of a grant I have held since 2006), I propose to expand on our discoveries of specific populations of nerve cells in the spinal cord, and to outline the roles of these cells in movement. I propose to study two particular populations of neurons - one that is hypothesised to play an important role in the generation of the rhythm of walking, and a second that is important for integrating information from the skin into the circuits that produce walking. I propose that this latter population is critical for the recovery of motor function following spinal cord injury. By outlining the function of these two populations of neurons, we will gain important foundational knowledge about how the spinal cord works to produce normal movement. In addition, we will be taking a step towards understanding how sensory information can lead to motor circuit plasticity following neurological injury. This knowledge will be important for the development of strategies to restore movement in people with neurological diseases or injuries that impair their ability to move.