What you read versus what you know: Neural correlates of accessing context information and background knowledge in constructing a mental representation during reading

A core issue in psycholinguistic research is what the online processes are by which we combine language input and our background knowledge to construct the meaning of a message. We investigate this issue in the context of reading. To build a coherent and correct mental representation of a text readers monitor incoming information for consistency with the preceding text and with their background knowledge. Prior studies have not distinguished between text-based and knowledge-based monitoring, therefore it is unclear to what extent these two aspects of text comprehension proceed independently or interactively. We addressed this issue in a contradiction paradigm with coherent and incoherent versions of texts. We combined behavioral data with neuroimaging data to investigate shared and unique brain networks involved in text-based and knowledge-based monitoring, focusing on monitoring processes that affected long-term memory representations. Consistent with prior findings, behavioral results indicate that text and background knowledge each have a unique influence on processing. However, neuroimaging data suggests a more nuanced interpretation: Text-based and knowledge-based monitoring involve shared and unique brain regions, as well as regions that are sensitive to interactions between the two sources. It appears that the (d)mPFC and hippocampus—which are important for the influence of existing knowledge on encoding processes in nonreading contexts—are particularly involved in knowledge-based monitoring. In contrast, the right IFG is primarily involved in text-based monitoring, whereas left IFG and precuneus are implicated in integration processes. Furthermore, processes during reading affect recall of information (in)consistent with prior text or background knowledge.