Effects of Observing Different Portions of the Reach-to-Grasp Movement on Neural Activation: an Electroencephalography Study

[Purpose] In this study, we examined the effects of observing different parts of the reach-to-grasp movement on neural activation using electroencephalography. [Subjects] The subjects were 12 right-handed, healthy adults. [Methods] The subjects were instructed to observe the entire reach-to-grasp movement, only the proximal part of the reach-to-grasp movement, or only the distal part of the reach-to-grasp movement. We studied the effect on mu suppression of observation of the reach-to-grasp movement, and compared it with the baselines values. [Results] First, our results showed that for all conditions, the log ratio of mu power at the C3 and C4 regions while observing the reach-to-grasp movement was significantly lower than the baseline values. Second, our results showed that the log ratio of mu power when the subjects observed the entire reach-to-grasp movement was significantly lower thay when they observed only the proximal part or only the distal part of the reach-to-grasp movement. [Conclusion] Observing the entire reach-to-grasp movement was more effective at activating mirror neurons than observing only the proximal part or only the distal part of the reach-to-grasp movement.