Neural specialisation for concrete and abstract concepts revealed through meta-analysis

Identifying the brain systems that process concrete and abstract concepts is key to understanding the neural architecture of thought, memory and language. We review current theories of concreteness effects and test their neural predictions in a meta-analysis of 72 neuroimaging studies. Concrete concepts preferentially activated visual and action processing regions, particularly when presented in sentences, while abstract concepts preferentially activated networks for language, social cognition and semantic control. Specialisation for both concept types was present in the default mode network (DMN), with effects dissociating along a social-spatial axis. Concrete concepts generated greater activation in a medial temporal DMN component, implicated in constructing mental models of spatial contexts and scenes. Abstract concepts showed greater activation in frontotemporal DMN regions involved in theory-of-mind and language. These results support claims that generating models of situations and events is a core DMN function and indicate specialisation within DMN for different aspects of these models.