Spinal cord injury immediately changes the state of the brain.
Spinal cord injury can produce extensive long-term reorganization of the cerebral cortex. Little is known, however, about the sequence of cortical events starting immediately after the lesion. Here we show that a complete thoracic transection of the spinal cord produces immediate functional reorganization in the primary somatosensory cortex of anesthetized rats. Besides the obvious loss of cortical responses to hindpaw stimuli (below the level of the lesion), cortical responses evoked by forepaw stimuli (above the level of the lesion) markedly increase. Importantly, these increased responses correlate with a slower and overall more silent cortical spontaneous activity, representing a switch to a network state of slow-wave activity similar to that observed during slow-wave sleep. The same immediate cortical changes are observed after reversible pharmacological block of spinal cord conduction, but not after sham. We conclude that the deafferentation due to spinal cord injury can immediately (within minutes) change the state of large cortical networks, and that this state change plays a critical role in the early cortical reorganization after spinal cord injury.
Hospital Nacional de Parapléjicos, Servicio de Salud de Castilla-La Mancha, Toledo, Spain. jdaguilar@sescam.jccm.es
Juan
J
Aguilar
Desiré
D
Humanes-Valera
Elena
E
Alonso-Calviño
Josué G
JG
Yague
Karen A
KA
Moxon
Antonio
A
Oliviero
Guglielmo
G
Foffani
D000344:Afferent Pathways / Q000187:drug effects / Q000503:physiopathology; D000704:Analysis of Variance; D000818:Animals; D001703:Biophysics; D004195:Disease Models, Animal; D004558:Electric Stimulation / Q000379:methods; D004569:Electroencephalography / Q000379:methods; D005073:Evoked Potentials, Somatosensory / Q000187:drug effects / Q000502:physiology*; D008012:Lidocaine / Q000494:pharmacology; D035002:Lower Extremity / Q000294:innervation; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D026941:Sodium Channel Blockers / Q000494:pharmacology; D013003:Somatosensory Cortex / Q000503:physiopathology*; D013119:Spinal Cord Injuries / Q000473:pathology*; D013223:Statistics as Topic; D013779:Tetrodotoxin / Q000494:pharmacology
D026941:Sodium Channel Blockers; D013779:Tetrodotoxin; D008012:Lidocaine