The effect of action experience on sensorimotor EEG rhythms during action observation.

A recent line of inquiry has examined how an observer׳s experience with action changes the neural processing of similar actions when they are subsequently observed. The current study used electroencephalography (EEG) to test the hypothesis that giving participants different types and amounts of experience with specific objects would lead to differential patterns of sensorimotor rhythms during the observation of similar actions on those objects. While EEG was recorded, three groups of participants (n=20 in each group; mean age=22.0 years, SD=2.7) watched video clips of an actor reaching, grasping, and lifting two objects. Participants then received information about differences in weight between the two objects. One group gained this information through extended sensorimotor experience with the objects, a second group received much briefer sensorimotor experience with the objects, and the third group read written information about the objects׳ weights. Participants then viewed the action sequences again. For participants who had sensorimotor experience with the objects, the EEG response to viewing the actions was differentially sensitive to the anticipated weight of the objects. We conclude that this sensitivity was based on the participant׳s prior sensorimotor experience with the objects. The participants who only received semantic information about the objects showed no such effects. The primary conclusion is that even brief experience with actions affects sensorimotor cortex activity during the subsequent observation of similar actions.