Successful discourse comprehension relies on reference to the previous discourse context and sometimes requires pragmatic inference from the global semantic meaning of the discourse. We used functional magnetic resonance imaging (fMRI) to investigate which brain regions are involved in reference processes under different circumstances.
To investigate reference processes, we presented short German discourses containing fulfilled and unfulfilled presuppositions, triggered by a definite or indefinite noun phrase. In one set of sentences, a contextual referent was explicitly mentioned as existent (e.g., “a rope”, in German “ein Seil”) or negated (“no rope”, in German “kein Seil”) in a context close or far away from the triggering noun phrase (memory context). In another set of sentences, a referent was not explicitly mentioned in the context, but an inference to a referent was either plausible or implausible due to contextual semantic relations (inference context). After listening to the spoken discourse, participants were asked to rate the coherence of the discourse.
Brain activation patterns showed that different areas were involved in the two different context conditions. In the memory condition, areas associated with phonological processes (e.g., supramarginal gyrus) and attention (e.g., insula / putamen) were active, whereas in the inference condition, areas associated with semantic processing (middle temporal gyrus) and episodic memory (fusiform gyrus / parahippocampus) were active. Taken together, our data show that discourse references in different contextual situations involve different brain areas and help to identify the neuronal network responsible for semantic and pragmatic discourse comprehension.