The hippocampus assumes a special role in supporting abstract concept representation

Unlike images, words are representational symbols. The associative details inherent within a words meaning and the visual imagery it generates, are inextricably connected to the way words are processed and represented. It is well recognised that the hippocampus associatively binds components of a memory to form a lasting representation, and here we show that the hippocampus is especially sensitive to abstract word processing. Using fMRI during recognition we found that the increased abstractness of words produced increased hippocampal activation and that critically this was independent of memory. Interestingly, word recollection produced hippocampal activation independent of word abstractness, while the parahippocampal cortex was sensitive to concrete word representation, independent of memory. We reason that the hippocampus has assumed a critical role in the representation of uncontextualized abstract word meaning, as its information-binding ability allows the retrieval of the semantic and visual associates that, when bound together, generate the abstract concept represented by word symbols. These novel findings not only offer insights for research drawing on word representation, memory, and hippocampal integrity, but critically, they throw important light on how the human brain may have adapted to encode and represent abstract words and concepts as they emerged in our language.