Differences of the frontal activation patterns by finger and toe movements: a functional MRI study.

It is well-known that physical exercise can affect cognition and the frontal lobe is an important structure involved in motor function and cognition. Furthermore, many functional neuroimaging studies have demonstrated that cortical activation patterns of hand and leg movements differ. However, no study has been undertaken to identify differences between the frontal activation patterns generated by hand and leg movements. In the present study, the frontal activation patterns associated with finger and toe movements, as visualized by functional MRI, were investigated and compared. Twelve healthy volunteers were recruited. Functional MRI was performed using a 1.5 T Philips Gyroscan Intera. Flexion-extension movements of fingers or toes were performed in one extremity. Regions of interest (ROIs) were set at the primary sensory-motor cortex (SM1: Brodmann area [BA] 1, 2, 3, 4), the premotor area (PMA: BA 6), and the prefrontal cortex (PFC: BA 8, 9, 10, 11, 46). In SM1, finger movements (10,809) induced more activation than toe movements (5349). On the other hand, in the PMA and PFC, toe movements (PMA: 4201, PFC: 921) induced more activation than finger movements (PMA: 2887, PFC: 912) respectively. In the analysis of relative voxel counts in the PMA and PFC versus the SM1, toe movements generated more activation in the PMA and PFC than finger movements. The PMA and PFC were more activated by toe than finger movements, although the SM1 was more activated by finger movements.