Discourse-level comprehension engages medial frontal Theory of Mind brain regions even for expository texts

ABSTRACT

In addition to understanding individual word meanings and processing the syntactic and semantic dependencies among those words within a sentence, language comprehension often requires constructing a higher-order discourse structure based on the relationships among clauses and sentences in the extended context. Prior fMRI studies of discourse-level comprehension have reported greater activation for texts than unconnected sentences in what-appear-to-be regions of the Theory of Mind (ToM) network. However, those studies have generally used narratives rich in mental state content, thus confounding coherence and content. We report an fMRI experiment where ToM regions were defined functionally in each participant, and their responses were examined to texts vs. sentence lists. Critically, we used expository texts to minimise mental state content. Medial frontal but not posterior ToM regions exhibited small but reliable increases in their responses to texts relative to unconnected sentences, suggesting a role for these regions in discourse comprehension independent of content.

KEYWORDS:

• Coherence
• discourse
• fMRI
• Theory of Mind network

Acknowledgments

We thank (i) Jeanne Gallée for help in creating the materials, (ii) Ted Gibson for help in running the self-paced reading study, (iii) Zach Mineroff and other EvLab members for help with scanning, and (iv) Zach Mineroff and Matt Siegelman for help with the website.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The authors would also like to acknowledge the Athinoula A. Martinos Imaging Center at the McGovern Institute for Brain Research at the Massachusetts Institute of Technology (MIT), and the support team (Steven Shannon, Atsushi Takahashi, and Sheeba Arnold). This research was supported by a grant from the Simons Foundation to the Simons Center for the Social Brain at MIT. E.F. was additionally supported by NIH awards R00-HD-057522 and R01-DC-016607. N.J. is supported by National Science Foundation Graduate Research Fellowship [grant number DGE 16-44869].