It is now well established that mental practice using motor imagery improves motor skills. The effects of mental practice on motor skill learning are the result of practice on central motor programming. According to this view, it seems logical that mental practice should modify the neuronal activity in the primary sensorimotor areas. This article explores the use of independent component analysis (ICA) approach to characterize the effect of mental practice and concentration skills on EEG patterns during motor imagery. The results indicate that the mental training has a significant effect on spatial-temporal EEG during motor imagery. It is observed that the power of delta and theta bands increases following the visual cue and alpha activity is significantly suppressed. Increase of gamma activities starts almost 1000 ms after the visual stimulus and continues to the end of imagination. Increase of theta activities can be associated with engagement of the working memory during motor imagery and represents the memory load. The interesting result is that the mental training dramatically enhances motor-cortex rhythm. It is found that ICA can successfully detect and separate different brain activities into separate components during motor imagery.