Here we highlight collaborative projects supported by the Consortium
Corticospinal neurons encode complex motor signals that are broadcast to dichotomous striatal circuits
Anders Nelson, Brenda Abdelmesih, Rui M Costa
BioRxiv July 21 (2020)
Animals interact with their environments through movement, the product of precisely patterned activation of spinal circuits that control body muscles, as well as the myriad brain regions that are integral to controlling these circuits. How is it that widespread and diverse brain regions can act together and not send conflicting information to the spinal cord? One idea is that a specialized neuronal pathway broadcasts a signal to all of these brain and spinal regions simultaneously, in effect telling these downstream regions to keep their activity in lock step. A good contender for this specialized role is the corticospinal pathway, because it contains neurons that send long-range projections not only to the spinal cord, but also to most of the other brain regions that are involved in generating movements. While corticospinal neurons have been known for well over a century, neuroscientists understand remarkably little about how they are organized, what types of cells they communicate with in downstream brain regions, and what information they encode in their activity. Our paper uses a range of advanced techniques to map the projections of corticospinal neurons and identify the cell types that they target in different brain and spinal regions. We identified unexpected complexities in this pathway, like the fact that different groups of corticospinal neurons target different cell types in downstream brain and spinal regions. We also showed that these neurons encode surprisingly complex information like sequences of movements, rather than only muscle activity. Altogether, our results reveal the biological principles that underlie the corticospinal pathway, and move us closer to understanding how these unique cells coordinate the brain and spinal structures that are necessary for behavior.