CORTICAL LOCALIZATION OF MAGNETIC-FIELDS EVOKED BY ESOPHAGEAL DISTENSION

Magnetoencephalographic source localisation techniques were used to me asure oesophageal evoked magnetic fields from the cerebral cortex in 3 subjects. By using rapid balloon distension as a stimulus, a comparis on of proximal and distal oesophageal cortical representation was made . The distal oesophagus was represented bilaterally in the insular cor tex and SII as well as the inferior aspect of SI. The proximal oesopha gus was represented unilaterally in superior and inferior SI, insular cortex and SII. Significantly, the superior portion of SI was consiste ntly activated in subjects following stimulation of the proximal oesop hagus, but similar activation was not found in response to distal stim ulation. This may reflect the contribution from somatic afferent fibre s in the striate muscle of the proximal segment. In conclusion, vagal afferents appear to contribute more to cortical activation following s timulation of the distal rather than the proximal oesophagus, while sp inal afferents appear to be activated by both proximal and distal oeso phageal stimulation. (C) 1998 Elsevier Science Ireland Ltd.