PMID- 17913768 OWN - NLM STAT- MEDLINE DCOM- 20071213 LR - 20161124 IS - 1460-2156 (Electronic) IS - 0006-8950 (Linking) VI - 130 IP - Pt 11 DP - 2007 Nov TI - Cortical sensory map rearrangement after spinal cord injury: fMRI responses linked to Nogo signalling. PG - 2951-61 AB - Cortical sensory maps can reorganize in the adult brain in an experience-dependent manner. We monitored somatosensory cortical reorganization after sensory deafferentation using functional magnetic resonance imaging (fMRI) in rats subjected to complete transection of the mid-thoracic spinal cord. Cortical representation in response to spared forelimb stimulation was observed to enlarge and invade adjacent sensory-deprived hind limb territory in the primary somatosensory cortex as early as 3 days after injury. Functional MRI also demonstrated long-term cortical plasticity accompanied by increased thalamic activation. To support the notion that alterations of cortical neuronal circuitry after spinal cord injury may underlie the fMRI changes, we quantified transcriptional activities of several genes related to cortical plasticity including the Nogo receptor (NgR), its co-receptor LINGO-1 and brain derived neurotrophic factor (BDNF), using in situ hybridization. We demonstrate that NgR and LINGO-1 are down-regulated specifically in cortical areas deprived of sensory input and in adjacent cortex from 1 day after injury, while BDNF is up-regulated. Our results demonstrate that cortical neurons react to sensory deprivation by decreasing transcriptional activities of genes encoding the Nogo receptor components in the sensory deprived and the anatomically adjacent non-deprived area. Combined with the BDNF up-regulation, these changes presumably allow structural changes in the neuropil. Our observations therefore suggest an involvement of Nogo signalling in cortical activity-dependent plasticity in the somatosensory system. In spinal cord injury, cortical reorganization as shown here can become a disadvantage, much like the situation in amblyopia or phantom sensation. Successful strategies to repair sensory pathways at the spinal cord level may not lead to proper reestablishment of cortical connections, once deprived hind limb cortical areas have been reallocated to forelimb use. In such situations, methods to control cortical plasticity, possibly by targeting Nogo signalling, may become helpful. FAU - Endo, Toshiki AU - Endo T AD - Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden. toshiki.endo@ki.se FAU - Spenger, Christian AU - Spenger C FAU - Tominaga, Teiji AU - Tominaga T FAU - Brene, Stefan AU - Brene S FAU - Olson, Lars AU - Olson L LA - eng PT - Journal Article PT - Research Support, Non-U.S. Gov't DEP - 20071003 PL - England TA - Brain JT - Brain : a journal of neurology JID - 0372537 RN - 0 (Brain-Derived Neurotrophic Factor) RN - 0 (GPI-Linked Proteins) RN - 0 (Myelin Proteins) RN - 0 (Nogo Receptor 1) RN - 0 (RNA, Messenger) RN - 0 (Receptors, Cell Surface) RN - 0 (Receptors, Peptide) RN - 0 (Rtn4r protein, rat) RN - EC 4.1.1.15 (Glutamate Decarboxylase) RN - EC 4.1.1.15 (glutamate decarboxylase 1) SB - IM MH - Afferent Pathways/physiology MH - Animals MH - Brain-Derived Neurotrophic Factor/genetics MH - Down-Regulation MH - Electric Stimulation MH - Female MH - Forelimb MH - GPI-Linked Proteins MH - Glutamate Decarboxylase/genetics MH - In Situ Hybridization MH - *Magnetic Resonance Imaging MH - Models, Animal MH - Myelin Proteins MH - Neuronal Plasticity/*physiology MH - Nogo Receptor 1 MH - Phantom Limb/physiopathology MH - RNA, Messenger/analysis MH - Rats MH - Rats, Sprague-Dawley MH - Receptors, Cell Surface MH - Receptors, Peptide/genetics/*metabolism MH - Somatosensory Cortex/metabolism/*physiopathology MH - Spinal Cord Injuries/metabolism/*physiopathology MH - Time Factors EDAT- 2007/10/05 09:00 MHDA- 2007/12/14 09:00 CRDT- 2007/10/05 09:00 PHST- 2007/10/05 09:00 [pubmed] PHST- 2007/12/14 09:00 [medline] PHST- 2007/10/05 09:00 [entrez] AID - awm237 [pii] AID - 10.1093/brain/awm237 [doi] PST - ppublish SO - Brain. 2007 Nov;130(Pt 11):2951-61. doi: 10.1093/brain/awm237. Epub 2007 Oct 3.