The execution of complex motor actions, such as performing musical chords, demands considerable cognitive effort and engages multiple brain regions. Electroencephalography (EEG), a non-invasive technique with high temporal resolution, enables analysis of cortical activity associated with cognitive load, particularly in the alpha frequency band (7–13 Hz). In this study, we recorded alpha oscillations during repeated musical chord performances and during a simple control gesture. Assuming that the control gesture maintained a constant energy distribution, chord executions were compared across successive blocks of ten trials. Cosine-similarity analyses of alpha power distributions indicated low initial spatial correspondence that increased progressively with repetition. We identified the cortical region exhibiting the greatest linear increase in alpha-band activity via the coefficient of determination (R2). The results show a gradual transition from dispersed to more focused cortical patterns with practice, suggesting that alpha oscillations serve as sensitive neural markers of motor learning and task automatization.