Does a motor task resemble a linguistic task? Emprirical evidences on N400 effect

Introduction: the embodied cognition theories of language demonstrated the relationship between linguistic system and motor system. In the present study we investigated whether the action system produced a semantic response (N400 ERP index) similar to the linguistic system. Methods: fifteen subject saw a sequence of action and performed an explicit task to distinguish congruous from incongruous final target action. Plausible or implausible actions were performed within a contextual frame. Subjects perceived a semantic anomaly, that was a final target action that was not adequate (unusual) (Experiment 1) or not correctly performed (incorrect) (Experiment 2) with respect of the semantic properties required for the central action-goal. Results: ERP analysis showed a significant N400-like effect more frontally distributed in response to incongruous conditions for both the Experiments. Nevertheless, a more temporo-parietal cortical distribution was observed in case of an unusual way to perform the object-related action more than in case of an incorrect way. Conclusions: the N400-like effect is similar in nature to that which is generally evoked by linguistic stimuli, and this result may support the explanation of a N400 increasing based on the difficulty to access to the semantic memory. The temporo-parietal cortical distribution may be explained by assuming that in the Experiment 1 the relationship between the action and its intentional goals was violated.