ERP-based evidence for the independent processing of structural and functional action semantics.

In this study, the semantic processing and neural mechanisms of manipulative actions, categorized as structural actions and functional actions, were examined to assess whether these action types involve independent cognitive processes. Using a cue-stimulus paradigm with event-related potentials (ERPs), we analyzed neural responses to various manipulative actions. Manipulating the semantic congruency of structural actions (congruent vs. incongruent) and functional action types (wave vs. press) revealed distinct neural patterns. We observed distinct neural differences for functional actions in the 30-44 ms, 144-194 ms, 218-232 ms, 300-400 ms, and 562-576 ms windows. Early activation occurred in the left medial superior frontal gyrus, whereas sustained activity spread from the occipital and parietal regions to frontal regions between 144-194 ms and 300-400 ms. Late activation, occurring in the 562-576 ms window, was localized to the left middle frontal gyrus, right orbital inferior frontal gyrus, and right superior occipital gyrus. For structural actions, neural differences emerged in the 456-470 ms and 610-660 ms windows, which activated the parietal and temporal regions, including the left postcentral gyrus and right middle temporal gyrus. These findings suggest that the semantic processing of structural actions is partially independent of functional action cognition at the neural level.