Time-to-target simplifies optimal control of visuomotor feedback responses

Abstract

Visuomotor feedback responses vary in intensity throughout a reach, commonly explained by optimal control. Here we show that the optimal control for a range of movements with the same goal can be simplified to a time-to-target dependent control scheme. We measure participants visuomotor responses in five reaching conditions, each with different hand or cursor kinematics. Participants only produced different feedback responses when these kinematic changes resulted in different times-to-target. We complement our experimental data with a range of finite and non-finite horizon optimal feedback control models, finding that only the model with time-to-target as one of the input parameters can successfully replicate the experimental data. Overall, this suggests that time-to-target is a critical control parameter in online feedback control. Moreover, we propose that for a specific task and known dynamics, humans can instantly produce a control signal without any computation allowing rapid response onset and close to optimal control.