"Motor Primitives in Space and Time via Targeted Gain Modulation in Cortical Networks"

Our paper officially came out in Nature Neuroscience today! Here are some details.

Title: Motor Primitives in Space and Time via Targeted Gain Modulation in Cortical Networks

Authors: Jake P. Stroud, Mason A. Porter, Guillaume Hennequin, and Tim P. Vogels

Abstract: Motor cortex (M1) exhibits a rich repertoire of neuronal activities to support the generation of complex movements. Although recent neuronal-network models capture many qualitative aspects of M1 dynamics, they can generate only a few distinct movements. Additionally, it is unclear how M1 efficiently controls movements over a wide range of shapes and speeds. We demonstrate that modulation of neuronal input–output gains in recurrent neuronal-network models with a fixed architecture can dramatically reorganize neuronal activity and thus downstream muscle outputs. Consistent with the observation of diffuse neuromodulatory projections to M1, a relatively small number of modulatory control units provide sufficient flexibility to adjust high-dimensional network activity using a simple reward-based learning rule. Furthermore, it is possible to assemble novel movements from previously learned primitives, and one can separately change movement speed while preserving movement shape. Our results provide a new perspective on the role of modulatory systems in controlling recurrent cortical activity.