Distinct neural networks relate to common and speaker-specific language priors


Effective natural communication requires listeners not only to incorporate very general linguistic principles which evolved during a life time, but also other information like the specific individual language use of a particular interlocutor. Traditionally, research has focused on the general linguistic rules and brain-science has shown a left hemispheric fronto-temporal brain network related to this processing. The present fMRI-research explores speaker-specific individual language use because it is unknown whether this processing is supported by similar or distinct neural structures. Twenty-eight participants listened to sentences of persons who spoke easy or more difficult. This was done by manipulating the proportion of easy SOV vs. complex OSV sentences for each speaker. Furthermore, ambiguous probe sentences were included to test top-down influences of speaker information in the absence of syntactic structure information. We observed distinct neural processing for syntactic complexity and speaker-specific language use. Syntactic complexity correlated with left frontal and posterior temporal regions. Speaker-specific processing correlated with bilateral (right-dominant) fronto-parietal brain regions. Finally, the top-down influence of speaker information was found in frontal and striatal brain regions, suggesting a mechanism for controlled syntactic processing. These findings show distinct neural networks related to general language principles as well as speaker-specific individual language use.

Cerebral Cortex Communications