Motor related potential amplitude and latency shifts with repetitive task execution as an indication of motor adaptation

Abstract

Motor Related Potentials (MRPs) measure cortical activity relative to a motion task. We evaluated MRPs for a repetitive wrist flexion/extension task to identify changes in the signal characteristics that are indicative of task performance and motor adaptation. Our experiment consisted of a custom-built isometric joystick that controls a cursor on screen, while EEG and EMG data are recorded. The participants (6 healthy adults) performed more than 60 task repetitions, including flexion, extension, and alternating wrist movements while using the joystick. Task performance was tracked as successes or failures based on the individual’s ability to move the cursor to a target and hold the position. Our results show that MRP latency changes gradually with consecutive successful tasks (13–35%), and changes more abruptly (random) with failed tasks. Similarly, failed tasks see, on average, a 133.6 ms longer latency than successful tasks. Finally, statistical evaluation of MRP features identified three significant characteristics that can be used to distinguish between successful and failed tasks (Max Amplitude, Min Amplitude, P–P Amplitude). This research suggests that MRPs change with motor adaptation and performance for volitional reaching tasks. We propose that long-term applications of this research include measuring learning rates and performance outcome predictions for healthy and impaired motor control assessment.