The spread of technological instruments has simplified our lives, allowing us to easily accomplish many complex actions; thus, people are used to interacting with technological instruments and controlling them with simple movements. For instance, in our daily lives, we frequently press a button to switch channels on the TV, to call an elevator, to send e-mails on a computer, or to perform an “out and out” action, i.e., while playing video games. Thus, a very simple movement, such as a key-press, can have multiple meanings and different outcomes.
So far, it is not clear whether the motor preparation of an action, such as a key-press, could vary with the additional meaning of that action, i.e., when the key-press produces a specific consequence. Alternatively, the preparation might be entirely defined by the kinematics of the movement, which, obviously, does not change with the specific result of the action. We evaluated whether the brain activity preceding a simple action is modulated by the expected consequences of the action itself. To further this aim, the motor-related cortical potentials were compared during two key-press actions that were identical from the kinematics point of view but different in both meaning and consequences. In one case (virtual grasp), the key-press started a video clip showing a hand moving toward a cup and grasping it; in the other case, the key-press did not produce any consequence (key-press). A third condition (real grasp) was also compared, in which subjects actually grasped the cup, producing the same action presented in the video clip.
The results showed that motor preparation for virtual grasp (starting 3 s before the movement onset) was different from that of the key-press and similar to the real grasp preparation–as if subjects had to grasp the cup in person. In particular, both virtual and real grasp presented a posterior parietal negativity preceding activity in motor and pre-motor areas. In summary, this finding supports the hypothesis that motor preparation is affected by the meaning of the action, even when the action is only virtual.