Rewiring of hindlimb corticospinal neurons after spinal cord injury.
Little is known about the functional role of axotomized cortical neurons that survive spinal cord injury. Large thoracic spinal cord injuries in adult rats result in impairments of hindlimb function. Using retrograde tracers, we found that axotomized corticospinal axons from the hindlimb sensorimotor cortex sprouted in the cervical spinal cord. Mapping of these neurons revealed the emergence of a new forelimb corticospinal projection from the rostral part of the former hindlimb cortex. Voltage-sensitive dye (VSD) imaging and blood-oxygen-level-dependent functional magnetic resonance imaging (BOLD fMRI) revealed a stable expansion of the forelimb sensory map, covering in particular the former hindlimb cortex containing the rewired neurons. Therefore, axotomized hindlimb corticospinal neurons can be incorporated into the sensorimotor circuits of the unaffected forelimb.
Ghosh
Arko
A
Brain Research Institute, University of Zurich and Swiss Federal Institute of Technology Zurich, Zurich, Switzerland. arko@ini.phys.ethz.ch
Haiss
Florent
F
Sydekum
Esther
E
Schneider
Regula
R
Gullo
Miriam
M
Wyss
Matthias T
MT
Mueggler
Thomas
T
Baltes
Christof
C
Rudin
Markus
M
Weber
Bruno
B
Schwab
Martin E
ME
D000818:Animals; D019771:Axotomy / Q000379:methods; D001522:Behavior, Animal; D001931:Brain Mapping; D002574:Cervical Vertebrae; D004195:Disease Models, Animal; D005260:Female; D005456:Fluorescent Dyes; D005552:Forelimb / Q000503:physiopathology; D006614:Hindlimb / Q000503:physiopathology*; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods; D008564:Membrane Potentials / Q000502:physiology; D009044:Motor Cortex / Q000098:blood supply / Q000503:physiopathology; D009416:Nerve Regeneration / Q000502:physiology*; D010100:Oxygen / Q000097:blood; D011712:Pyramidal Tracts / Q000098:blood supply / Q000473:pathology*; D011720:Pyrazoles; D051381:Rats; D011917:Rats, Inbred Lew; D013119:Spinal Cord Injuries / Q000473:pathology* / Q000503:physiopathology*; D018709:Statistics, Nonparametric; D013844:Thiazoles
D005456:Fluorescent Dyes; D011720:Pyrazoles; C471342:RH1691; D013844:Thiazoles; D010100:Oxygen