Affiliations: Institute of Medical Psychology and Behavioral
Neurobiology, University of Tübingen, Germany | Department of Neurology, University of Tübingen,
Germany | Department of Neurology and Clinical Neurophysiology,
Academic Hospital Munich-Bogenhausen, Technical University Munich,
Germany
Note: [] Address for correspondence: Martin Lotze, MD, Institute for
Medical Psychology and Behavioral Neurobiology, University of Tübingen,
Germany, Gartenstrasse 29, D – 72074 Tübingen. Tel.: +49 7071
2974224; Fax: +49 7071 295956; E-mail: [email protected]
Abstract: Purpose: After a spinal cord injury (SCI), which was complete,
deafferentation of the body representation caudal to the lesion height results
in drastic changes in the cortical representation. The underlaying processes
are poorly understood. Methods: We investigated cortical representation sites of
upper limb muscles using functional magnetic resonance imaging (fMRI) and
transcranial magnetic stimulation (TMS) in five patients suffering from
thoracic complete SCI and one with an incomplete SCI in the height of L1. Results: In comparison to healthy controls fMRI demonstrated a
displacement of elbow movement representations in the precentral gyrus in
patients with complete SCI into the direction of the deafferented cortical
thoracic representation. Changes increased with time after the incidence of
SCI. TMS revealed reduced excitability and prolonged silent periods for muscles
more distant to the deafferented area. Conclusions: Whereas fMRI demonstrated changes in
representation sites adjacent to the deafferented area, TMS excitability
changes were also observed more distant to the deafferented area and silent
periods were prolonged in comparison to healthy controls. TMS changes might
depend on both: the distance to the deafferented area and the time of
persistence of deafferentation.
Keywords: SCI, reorganization, amputation, cortical plasticity, deafferentation, motor
