Objective
To evaluate the characteristics of the motor evoked potentials (MEPs) and the cortical topography of swallowing muscles in healthy subjects. Method: Fourteen healthy subjects were enrolled. Their mean age was 31 years. Transcranial magnetic stimulation was applied to left and right motor cortices in turn and contralateral electromyographic recordings were done from orbicularis oris, masseter, submental and infrahyoid muscles during resting. The scalp sites of maximal response and the lowest stimulus output which elicited motor evoked potential (MEP) of these muscles were recorded. The onset latency and peak-to-peak amplitude of MEP were measured for each muscle. Results: Most of the maximal MEPs of swallowing muscles were evoked within 9~17 cm lateral and 1~5 cm anterior from Cz and they showed interhemispheric symmetry. In submental and infrahyoid muscles, the threshold of right cortical excitability was significantly lower than that of left cortical excitability. The latency of the left submental MEP was statistically shorter than that of right submental MEP. Conclusion: These results demonstrated that the cortical representation of swallowing muscles displays interhemis-pheric symmetry. In addition, we suggest that submental and infrahyoid muscles have right cortical dominant tendency. (J Korean Acad Rehab Med 2009; 33: 154-158)