Rewiring of hindlimb corticospinal neurons after spinal cord injury

• Published in: Nature neuroscience Vol. 13; no. 1; pp. 97 - 104
• Main Authors: Ghosh, Arko, Haiss, Florent, Sydekum, Esther, Schneider, Regula, Gullo, Miriam, Wyss, Matthias T, Mueggler, Thomas, Baltes, Christof, Rudin, Markus, Weber, Bruno, Schwab, Martin E
• Format: Journal Article
• Language: English
• Published: New York Nature Publishing Group US 01.01.2010; Nature Publishing Group
• Subjects: Animal Genetics and Genomics; Animals; Axotomy - methods; Behavior, Animal; Behavioral Sciences; Biological Techniques; Biomedical and Life Sciences; Biomedicine; Brain Mapping; Central nervous system diseases; Cervical Vertebrae; Complications and side effects; Diagnosis; Disease Models, Animal; Drug therapy; Female; Fluorescent Dyes; Forelimb - physiopathology; Hindlimb - physiopathology; Image Processing, Computer-Assisted - methods; Magnetic resonance imaging; Magnetic Resonance Imaging - methods; Medical examination; Membrane Potentials - physiology; Motor Cortex - blood supply; Motor Cortex - physiopathology; Motor neurons; Nerve Regeneration - physiology; Neurobiology; Neurons; Neurosciences; Oxygen - blood; Paralysis; Physiological aspects; Pyramidal Tracts - blood supply; Pyramidal Tracts - pathology; Pyrazoles; Rats; Rats, Inbred Lew; Risk factors; Spinal cord injuries; Spinal Cord Injuries - pathology; Spinal Cord Injuries - physiopathology; Statistics, Nonparametric; Thiazoles; United States; Switzerland
• ISSN: 1097-6256; 1546-1726
• DOI: 10.1038/nn.2448

In rodents, descending corticospinal tracts can be rerouted to innervate new targets after a spinal cord injury. Here, Ghosh et al . show that such anatomical rearrangement in the injured spinal cord is accompanied by sensory remapping at the cortical level. 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, axotomised hindlimb corticospinal neurons can be incorporated into the sensorimotor circuits of the unaffected forelimb.