Objective: A baseline functional magnetic resonance imaging (fMRI) study was carried out on a healthy right-handed male subject to attain further insights into the basic neuronal control mechanisms of bimanual and unimanual movements of hand fingers, an area that is still not fully understood. Methods : The study used the basic unimanual and bimanual movements of the left- and right-hand fingers to stimulate neuronal activity in the cerebral cortices. The subject was instructed to sequentially press his fingers either unimanually (UNI) or bimanually (BIM), against the thumb in a consistent alternative manner during the functional scans. The data were analysed using the MATLAB and SPM2 software packages. Results : Brain activations obtained via the F-test indicate a larger activation area as compared to that obtained from the T-test. The results showed that, the activated brain regions due to the self-paced finger movements are the precentral and postcentral gyrii covering the primary motor, premotor and somatosensory primer areas. The activestate signal intensity was found to be significantly (p < 0.05) higher than that of the resting-state. For UNI, brain activation showed contra-laterality with a larger activation area and a higher signal intensity at the point of maximum intensity for the left-hand finger
movement (UNIleft) compared to the right-hand finger movement (UNIright). Small ipsilateral activations were observed during UNIright and UNIleft. For BIM, the activation was observed in both hemispheres with the right hemisphere showing a higher signal intensity and coverage. The results support the fact that for a right-handed person performing either UNI or BIM type of movement, the activated motor area on the right hemisphere of the brain (movement of the left hand fingers) experience a higher intensity and larger coverage of hemodynamic response compared to the left hemisphere of the brain (movement of the right hand fingers). Analyses performed on the activated regions of interest (ROI) by
comparing the unimanual and bimanual types of activations revealed that during BIM, there are voxels in the left hemisphere controlling the movement of the left hand fingers (BIMleft) and voxels in the right hemisphere controlling the movement of the right hand fingers (BIMright). The interactions observed in this study resemble the existence of interhemispheric connection between both hemispheres during BIM. Conclusion : Although this is a single subject study, the hemodynamic response and the neuronal control mechanism in the cerebral cortices based on the BOLD mechanism can be studied and evaluated using fMRI and SPM.