title: Functional magnetic resonance imaging in rodents: Methodology and application to spinal cord injury.
abstract: Functional MRI (fMRI) on spinal cord-injured rodents at 4 and 8 weeks post injury (PI) is described. The paradigm for fMRI, based on electrical stimulation of rat paws, was automated using an in-house designed microprocessor-based controller that was interfaced to a stimulator. The MR images were spatially normalized to the Paxinos and Watson atlas using publicly available digital images of the cryosections. In normal uninjured animals, the activation was confined to the contralateral somatosensory cortex. In contrast, in injured animals, extensive activation, which included structures such as ipsilateral cortex, thalamus, hippocampus, and the caudate putamen, was observed at 4 and 8 weeks PI. Quantitative cluster analysis was carried out to calculate the volumes and centers of activation in individual brain structures. Based on this analysis, significant increase in activation between 4 and 8 weeks was observed only in the ipsilateral caudate putamen and thalamus. These studies suggest extensive and ongoing brain reorganization in spinal cord-injured animals.
authors.affiliation: Department of Diagnostic and Interventional Imaging, University of Texas Medical School at Houston, Houston, Texas 77030, USA.
authors.forename: Jaivijay
authors.initials: J
authors.lastname: Ramu
authors.forename: Kurt H
authors.initials: KH
authors.lastname: Bockhorst
authors.forename: Kishore V
authors.initials: KV
authors.lastname: Mogatadakala
authors.forename: Ponnada A
authors.initials: PA
authors.lastname: Narayana
mesh_terms: D000465:Algorithms; D000818:Animals; D001921:Brain / Q000473:pathology; D016000:Cluster Analysis; D003627:Data Interpretation, Statistical; D004558:Electric Stimulation; D005528:Foot / Q000502:physiology; D007839:Functional Laterality / Q000502:physiology; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D013116:Spinal Cord / Q000473:pathology; D013119:Spinal Cord Injuries / Q000473:pathology*