Functional magnetic resonance imaging (fMRI) is a non-invasive brain imaging technique widely used in the evaluation of the brain function that provides images with high temporal and spatial resolution. Investigation of the supplementary motor area (SMA) function is critical in the pre-surgical evaluation of neurological patients, since marked individual differences and complex overlapping with adjacent cortical areas exist, and it is important to spare the SMA from lesions when adjacent cortical tissue is surgically removed. We used fMRI to assess the activity of SMA in six right-handed and six left-handed healthy volunteers when a task requiring silent repetition of a series of words was given. Brain activation areas in each of the subjects were localized according to the standard Talairach coordinate space, and the individual voxels for each map were compared after 3D sagittal images were created and SMA was delimited. Quantitative analysis of hemispheric and bilateral SMA activation was described as mean ± standard deviation of hot points/total points. The results show that the language task induced bilateral SMA activation. Left SMA activation was significantly higher than right SMA activation in both right-handed and left-handed subjects.

Functional magnetic resonance imaging (fMRI) was used to assess the activity of supplementary motor area (SMA) in six right-handed and six left-handed healthy volunteers. Two manual tasks (self-initiated previously practiced and unpredictable visually guided) were used. Quantitative analysis of hemispheric and bilateral SMA activation was described as mean ± standard deviation of hot spots/total spots. The two tasks induced bilateral SMA activation. The laterality of SMA activation was affected by manual dominance. Left SMA was significantly more activated in rightand left-handers while performing the motor tasks with the right hand. Right SMA was more activated in the left-handers when the left hand was used. Task complexity was the most important factor influencing the degree of SMA activation.