The electrical and magnetical cerebral responses evoked by electrical stimulation of the esophagus and the location of their cerebral sources

Objectives: After electrical stimulation of the esophagus cerebral response s are recordable, their cortical source is under discussion. Brain mapping using electroencephalography recordings demonstrated partially controversia l results. Sources of evoked responses can be localized more easily using m agnetoencephalography than electroencephalography. Methods: We examined 22 volunteers by recording electrical somatosensory po tentials after electrical stimulation of the esophagus. In 9 of these 22 su bjects additional recording of magnetic fields was performed and the source s of the evoked magnetic fields were computed. Results: The evoked potentials after electrical stimulation of the esophagu s had a similar latency as the previously published data. The source locali zation done by magnetoencephalography suggest that first a region of the po stcentral gyrus is activated which is temporo-lateral to the primary somato sensory cortex of the pharynx. This region is suggested to be the primary s omatosensory region of the esophagus. This source was followed by a source in the parietal operculum thought being part of the secondary somatosensory cortex. Simultaneously the insular cortex was activated pointing to a para llel neuronal pathway to the central autonomic nervous system. Conclusion: After electrical stimulation of the esophagus somatosensory cor tical areas of the temporal postcentral gyrus and the operculum are activat ed. In parallel activation of the insular cortex as part of the central aut onomic network was found. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.