We investigated neurophysiologic correlates of individual differences in the modulation of sensorirnotor rhythms (SMRs) in the human electroencephalography (EEG) during motor imagery. The ability of modulating SMRs to different motor imageries was correlated with the strength of alpha phase synchronization across frontal and central sensorimotor areas. The results suggest that fronto-central coupling may elucidate individual variations in SMR modulation that is essential for using SMR-based brain-computer interfaces.