title: Immediate cortical reorganization after local anesthetic block of the thumb: source localization of somatosensory evoked potentials in human subjects.
abstract: Psychophysical observations after anesthesia of the thumb raise the question whether the functional border between the thumb and the index is functionally distinct. We present a source localization study using equivalent current dipole modeling of somatosensory evoked potentials (SEPs) following mechanical air-puff stimulation of the first, second and third digits before and during anesthesia of the thumb. Source reconstruction was based on 96-channel SEP recordings. During anesthesia of the thumb the distance between the cortical representation of the thumb and the second and third digits immediately decreased. This indicates a shift of the cortical representation of the second and third digits towards the deafferented area of the anesthetized thumb. Thus, the present results did not confirm the hypothesis of a functional border of the cortical representation between thumb and index finger in this particular task.
authors.affiliation: Department of Neurology, University Hospital Aachen, Pauwelsstrasse 30, D-52057, Aachen, Germany. till.waberski@post.rwth-aachen.de
authors.forename: T D
authors.initials: TD
authors.lastname: Waberski
authors.forename: R
authors.initials: R
authors.lastname: Gobbelé
authors.forename: W
authors.initials: W
authors.lastname: Kawohl
authors.forename: C
authors.initials: C
authors.lastname: Cordes
authors.forename: H
authors.initials: H
authors.lastname: Buchner
mesh_terms: D000328:Adult; D000344:Afferent Pathways; D000779:Anesthetics, Local; D002540:Cerebral Cortex / Q000502:physiology*; D005073:Evoked Potentials, Somatosensory / Q000187:drug effects*; D005260:Female; D006801:Humans; D008297:Male; D008619:Mepivacaine; D010812:Physical Stimulation; D013933:Thumb / Q000294:innervation*
chemical_list: D000779:Anesthetics, Local; D008619:Mepivacaine