Abstract
While the phenomena of motor adaptation and motor aftereffects are well documented, a full picture of the neural substrate underlying these phenomena remains elusive. The motor aftereffects generated when a force is removed that a subject has adapted to can be thought of as a motor error. The aim of this study was to determine whether cortical event-related potentials for motor errors could be detected. Participants made reaching movements and slowly adapted to a force that perturbed their reaches. On some trials the perturbing force was turned off without warning, and we found that this caused motor aftereffect errors. We compared the reaching movements made before the influence of a perturbing force to reaching movements made when the participant had fully adapted to a perturbing force and the force has been turned off. We found representative ERPs occurring at 255ms and 182ms for negativities and 345ms and 292ms for positivities at electrodes FCz and Cz. Amplitudes at these electrodes ranged from -41.4mV to -36.8mV for negativities to 32.7mV to 35.1mV for positivities. All subjects showed error-related negativities at FCz and Cz and 62.5% and 75% of subjects showed error-related positivities at FCz and Cz respectively. Error-related negativities for these modalities occur earlier. It is unclear whether this reflects a difference in error processing between the motor system and other modalities or a limitation in our method.