Motor expertise shapes crossmodal and modality-specific action representations in table tennis players.

Multivariate neuroimaging studies have shown a functional dissociation between the temporal and frontoparietal cortices in action representation. However, it remains unclear to what extent this specificity is modulated by motor experience. To address this question, we employed functional magnetic resonance imaging-based multivoxel pattern analysis (MVPA). Neural activation patterns were compared between professional table tennis players (experts) and novices during the passive observation of action videos and the reading of corresponding action-related sentences. Specifically, to identify brain regions that decode perceptual-motor information, classifiers were trained and tested within the same stimulus modality (video or sentence). To identify brain regions supporting conceptual-level action decoding, classifiers trained on video stimuli were tested on sentence stimuli, and vice versa. The results revealed that, in experts, the left lateral posterior temporal cortex (LPTC) and anterior temporal lobe (ATL) supported crossmodal action representations, whereas the left superior parietal lobule (SPL) and precentral gyrus (PreCG) exhibited modality-specific representations, particularly in response to video-based stimuli. In novices, only the PreCG showed modality-specific representations for video stimuli. These findings suggest a functional dissociation across brain regions, with the temporal cortex involved in conceptual-level representations of actions andthe SPL associated with processing perceptual-motor features. While such representations were more prominent in experts for familiar actions, the PreCG showed modality-specific representations regardless of group. These results highlight potential group-level differences in the neural encoding of action-related information, which may reflect the influence of task familiarity or prior sensorimotor experience.