Representation of event and object concepts in ventral anterior temporal lobe and angular gyrus

Abstract

Semantic knowledge includes understanding of objects and their features and also understanding of the characteristics of events. The hub-and-spoke theory holds that these conceptual representations rely on multiple information sources that are integrated in a central hub in the ventral anterior temporal lobes (vATL). Dual-hub theory expands this framework with the claim that the vATL hub is specialized for object representation, while a second hub in angular gyrus (AG) is specialized for event representation. To test these ideas, we used RSA, univariate and PPI analyses of fMRI data collected while participants processed object and event concepts (e.g., an apple, a wedding) presented as images and written words. RSA showed that AG encoded event concept similarity more than object similarity, although the left AG also encoded object similarity. Bilateral vATLs encoded both object and event concept structure, and left vATL exhibited stronger coding for events. PPI analysis revealed greater connectivity between left vATL and right pMTG, and between right AG and bilateral ITG and middle occipital gyrus, for event concepts compared to object concepts. These findings support the specialization of AG for event semantics, though with some involvement in object coding, but do not support vATL specialization for object concepts.