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Multiple frequency steady-state evoked magnetic field mapping of digit representation in primary somatosensory cortex |
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| Authors: | Eugen Diesch Hubert Preissl Max Haerle Hans-Eberhard Schaller Niels Birbaumer |
| Affiliation: | 1. Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Gartenstr. 29, 72074 Tübingen, Germany;2. MEG Center, University of Tübingen, Gartenstr. 29, 72074 Tübingen, Germany;3. Department of Plastic, Hand, and Burn Surgery, University of Tübingen, BG-Klinik, Gartenstr. 29, 72074 Tübingen, Germany;4. Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Gartenstr. 29, 72074 Tübingen, Germany and Dipartimento di Psicologia Generale, Universitádi Padova, Italy |
| Abstract: | Magnetic source imaging of multiple frequency steady-state somatosensory evoked responses was examined using a 151-channel magnetoencephalography (MEG) system and a dual-channel electrical stimulator. Somatotopy of digit representation was studied in healthy subjects and effects of injury-related cortical plasticity in patients with unilateral transections of the median or the ulnar nerve. Dipole source locations exhibited somatotopic order with overlap between neighboring digits. In two of three nerve injury patients evidence for cortical reorganization was found. The location of sources related to digits neighboring deafferented digits was changed and their dipole moments were enlarged by comparsion with the sources related to contralateral homologue control digits. As a basis for magnetic source imaging, the recording of multiple frequency somatosensory steady-state evoked responses may be a viable and time saving alternative to the recording of transient evoked responses. |
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