Brachial Plexus Injury In The Motor Cortex Functional Reorganization

PART ⅠSomatotopic mapping of the human primary motor cortex with functional MRI【Abstract】Purpose: The aim of this study was to apply functional magnetic resonance imaging to map the somatotopic organization of the primary motor cortex using voluntary movements of the hand, elbow, and the shoulder of both of the upper extremity to determine if the fMRI is capable of generating somatotopic maps of the primary motor cortex in individual subjects, and to explore the limitation of fMRI use. Materials and methods: 12 healthy volunteers were employed in this study, right handerness 10 cases and left handerness 2 cases. Motor task consisted of self-paced, repetitive simple movements of the upper limbs. fMRI examinations were performed by using a superconduct 1.5T MR scanner and echo-planer BOLD sequence was used. The position of the most significant voxel of activation area of the Talairach coordinates in the primary motor cortex was recorded and the statistic analysis of variance was used for values of the x axis, y axis and the z axis. Results: Statically significant MR signal changes were observed within contralateral primary motor cortex in all subjects and movement conditions. The pattern of functional activity followed a topographic representation: hand movements resulted in signal intensity changes over the lateral middle section of the primary motor cortex, whereas shoulder movements produced changes in the meddle-upper section of the primary motor cortex near the interhemispheric fissure. Elbow movements resulted signal changes between signalchanges observed with hand and shoulder movements and overlapped with them. Statistic analysis indicated that there were significant differences among hand and elbow as well as shoulder in x axis value. The z axis value between hand and shoulder also show significant difference. Conclusions: These findings indicate that fMRI is capable of generating somatotopic maps of the primary motor cortex in individual subjects.Key words: functional magnetic resonance imaging,brain,motor cortex...