Grant: Project Grant

The deliberate and precise movements of a watchmaker's fingers when repairing a tiny timepiece are examples of conscious control that our brain exerts over our muscles and joints. In contrast, during locomotion, many of our limbs' movements are controlled in an unconscious manner, yet with a very high degree of precision. For example, allowing a hockey goalie to accurately position their arms and legs to block a fast-moving puck, all in a fraction of a second. This is because when moving our limbs, our nervous system is constantly analysing sensory information about their position in three dimensions of space, whether they are touching an object, how far they are from it, their velocity, and many other parameters. The neurons and their networks that mediate this are the subject of this proposal. We discovered a population of spinal cord neurons that send an axon all the way to a region of the brain called the thalamus, which processes most sensory information about our body, before it reaches our cortex. The thalamus does not hold a prominent role in locomotion, so it was surprising to us when we discovered that ablating this population of neurons results in defective locomotion in mice. We propose to elucidate the precise function of these neurons by studying the sensory neurons that connect to them, their activity patterns, and the consequence of their silencing or activation during locomotion. It is likely that these neurons are also present in humans, and we hypothesise that they may be responsible for the fine and instantaneous adjustment of how our limbs move.