Movement-related potentials during the performance of a motor task I: The effect of learning and force

Movement-related potentials (MRPs) recorded from the brain may be affected by several factors. These include the how well the subject knows the task a nd the load against which he performs it. The objective of this study is to determine how dominant these two factors are in influencing the shape and power of MRPs. MRPs were recorded during performance of a simple motor task that required learning of a force. A stochastic algorithm was used in orde r to partition a set of MRPs that are embedded in the surrounding electroen cephalographic (EEG) activity into distinct classes according to the power of the underlying MR-Ps. Our results show that the most influential factor in the partition was the load against which the subject performed the task. Furthermore, it was found that learning has a smaller, though not insignif icant, influence on the power of the MRPs.