A technique called voxel-based lesion-symptom mapping allowed the team to pool data from the veterans' CT scans to create a collective, three-dimensional map of the cerebral cortex. They divided this composite brain into units called voxels (the three-dimensional counterparts of two-dimensional pixels). This allowed them to compare the discourse comprehension abilities of patients with damage to a particular voxel or cluster of voxels with those of patients without injuries to those brain regions.
The researchers identified a network of brain areas in the frontal and parietal cortex that are essential to discourse comprehension.
"Rather than engaging brain regions that are classically involved in language processing, our results indicate that discourse comprehension depends on an executive control network that helps integrate incoming language with prior knowledge and experience," Barbey said.
Executive control, also known as executive function, refers to the ability to plan, organize and regulate one's behavior.
"The findings help us understand the neural foundations of discourse comprehension, and suggest that core elements of discourse processing emerge from a network of brain regions that support language processing and executive functions. The findings offer new insights into basic questions about the nature of discourse comprehension," Barbey said, "and could offer new targets for clinical interventions to help patients with cognitive-communication disorders.
"Discourse comprehension is a hallmark of human social behavior," Barbey said.
"By studying the mechanisms that underlie these abilities, we're able to advance our understanding of the remarkable cognitive and neural architecture from which language comprehension emerges."
|Contact: Chelsey B. Coombs|
University of Illinois at Urbana-Champaign