Electromyographic (EMG) activity and MEP traces. A. typical example of electromyographic (EMG) activity elicited in the FDI muscle during performance of the two finger movement tasks (discrimination, TD; non discrimination, ND). Note the similarity between the two tasks (TD vs. ND) in terms of EMG patterns produced. B. Examples of task-specific facilitation recorded in the FDI in two individuals, one having high (100%) and another having low (56%) discrimination performance. Note the task-related increase in MEP amplitude in the TD condition in the younger senior with high discrimination performance, and the similarity in MEP amplitudes between the TD and ND conditions in the older senior with low discrimination performance.