Combination of TMS and fMRI reveals a specific pattern of reorganization in M1 in patients after complete spinal cord injury.
OBJECTIVE
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.
Lotze
M
M
Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Germany. martin.lotze@uni-tuebingen.de
Laubis-Herrmann
U
U
Topka
H
H
D000328:Adult; D000368:Aged; D001931:Brain Mapping; D016022:Case-Control Studies; D019054:Evoked Potentials, Motor / Q000502:physiology / Q000528:radiation effects; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000098:blood supply* / Q000503:physiopathology / Q000528:radiation effects; D009473:Neuronal Plasticity / Q000502:physiology / Q000528:radiation effects*; D010100:Oxygen / Q000097:blood; D013119:Spinal Cord Injuries / Q000175:diagnosis* / Q000503:physiopathology*; D050781:Transcranial Magnetic Stimulation
D010100:Oxygen