This study used electroencephalography (EEG) and Representational Similarity Analysis (RSA) to investigate whether the neural representation of a concept built from a descriptive sentence was similar to the representation evoked by the name of the concept alone. Fifteen students from Kyushu University (including 1 female; mean age = 23.5, standard deviation SD = 2.4 years) were recruited. Two experiments were conducted in Japanese language. In Experiment 1, a stable neural representation pattern (template Representational Dissimilarity Matrix RDM) for occupational concepts was identified by comparing the neural patterns evoked by occupation names and their synonyms. In Experiment 2, participants read a four-word sentence to identify an occupation, followed by a congruent (ANS/T) or incongruent (ANS/F) target word. Participants' self-reported timing of concept identification was also collected. A time-resolved RSA (using Spearman's correlation) was used to track template RDM reinstatement, with significance assessed by permutation test. Event-related potentials (ERPs) associated with the final target words were analyzed using a spatiotemporal cluster-based permutation test. The ERP analysis revealed a robust P300 (P3b) component for incongruent targets relative to congruent targets (significant positive cluster at Pz: 308-464 ms, P < .05), reflecting conscious target discrimination. The RSA showed no consistent reinstatement of the template pattern at the group level. However, at the individual level, the timing of neural reinstatement was associated, although non-uniformly, with the self-reported timing of subjective concept identification. These findings suggest that neural reinstatement of knowledge during contextual understanding is not uniformly linked to external stimuli, but is coupled with internal moments of concept identification, which vary across individuals owing to different cognitive strategies.
Iwata et al. (Thu,) studied this question.