Duration-modulated neural population dynamics in humans during BMI controls

The motor cortex (MC) is often described as an autonomous dynamical system during movement execution. In an autonomous dynamical system, flexible movement generation depends on reconfiguring the initial conditions, which then unwind along known dynamics. An open question is whether these dynamics govern MC activity during brain-machine interface (BMI) control. We investigate MC activity during BMI cursor movements of multiple durations, ranging from hundreds of milliseconds to sustained over seconds. These durations are chosen to cover the range of movement durations necessary to control modern BMIs under varying precision levels. Movements share their MC initial condition with movements of different durations in the same direction. Long-duration movements sustain MC activity in a low-velocity steady state until each movement goal is reached. The difference across durations in MC population dynamics may be attributed to external inputs. Our results highlight the role of sustained inputs to MC during movement.