Coherent representation of action sequences implies that the logical temporal order of each action can be correctly represented. Violation of this logical order may induce a sort of expectancies disruption of the temporal structure. Thus the present study explored the event-related potential (ERP) effect related to the cortical response to this violation. Action sequence composed by four frames with final congruous or incongruous endings was submitted to 28 subjects. Two distinct ERP effects, feedback-related negativity (FRN), and P300, were found in response to incongruous endings, with also significant increased RTs. The functional significance of these two ERP deflections was related respectively to the perception of an erroneous action outcome as the ending of an illogical sequence (FRN) and to the necessity to updating the relationship action-context by changing the cognitive model which supports the cognitive expectancies (P300). The significant correlation between the RTs and the ERP measures, especially in case of FRN effect, supported this interpretation. Indeed increased cognitive costs are supposed in case of expectancies violations which require further processes of reanalysis of the coherence between the action and the background (the temporal background) where the action was produced. Two different cortical localizations were found for FRN and P300, respectively a more fronto-central (dorsolateral prefrontal cortex) and posterior (superior temporal gyrus) site. The significance of these results for the temporal order effect for action comprehension was discussed.
- action representation
- temporal order