THE TOPOGRAPHIC REPRESENTATION OF ESOPHAGEAL MOTOR FUNCTION ON THE HUMAN CEREBRAL-CORTEX

Background & Aims: Corticofugal pathways to the human esophagus have b een recently identified in humans using transcranial magnetic stimulat ion, The aim of this study was to determine the topographic representa tion of the esophagus on the cerebral cortex. Methods: Focal magnetic stimulation of l-cm areas was performed over both hemispheres in 10 he althy subjects. Esophageal electromyographic responses were recorded 2 cm below the upper esophageal sphincter, The studies were repeated to determine reproducibility in 3 subjects; in 2 subjects, esophageal to pography was compared with thenar muscle topography, Results: In all s ubjects, esophageal electromyographic responses were evoked by stimula tion of either the right or left hemisphere, Largest amplitude respons es were obtained anterior to those of the thenar muscles, indicating t hat the esophagus may be represented on either the anterior aspect of the motor cortex or on the premotor cortex, In all subjects, the area of response was asymmetric, being more extensive on the right hemisphe re than on the left hemisphere in 8 subjects. In 2 subjects, the area of response on the left hemisphere was more extensive than on the righ t, Repeat studies showed that this asymmetry was consistent, Conclusio ns: Esophageal motor function shows bilateral cortical representation with consistent interhemispheric asymmetry.