OBJECTIVETo investigate the brain functional laterality in motor areas during motor execution systematically.

METHODSFunctional magnetic resonance imaging (fMRI) was employed combined with right hand sequential finger movement task to investigate brain activation pattern and laterality in 8 right-handed subjects. 3dDeconvolve program of AFNI was used to estimate the hemodynamic response function and to generate activation maps. Then the laterality index (LI) was calculated and tested statistically.

RESULTAll motor areas including the areas which were previously considered to be engage in movement preparation only were activated in movement execution. In the activation map, it appeared left lateralization in cerebra and right lateralization in cerebella. After further statistical test, it was found that in primary motor area (M1), supplementary motor area (SMA) and posterior parietal cortex (PPC), there were left lateralization. While in premotor cortex (PMC), cingulate gyrus and basal ganglia (BG), the lateralization tendency was not obvious. The activation in cerebella is characterized with right lateralization.

CONCLUSIONThough there are tiny differences among subjects, most of the motor areas appear lateralized activation. Past studies only observed laterality in several motor areas. It may be due to the difficulty of the task or the experimental design.