Role for Left Dorsomedial Prefrontal Cortex in Self-Generated, but not Externally Cued, Language Production

Area of Science:

• Neuroscience
• Linguistics
• Neurolinguistics

Background:

• The left dorsomedial prefrontal cortex (dmPFC) is recognized for its role in volition and motor control.
• Its specific contribution to language processing, particularly self-generated speech, is often underestimated in current neural models.

Purpose of the Study:

• To investigate the association between left dmPFC damage and a specific language profile.
• To determine if this profile is unique to dmPFC lesions and not caused by motivational or motor deficits.
• To add a patient-centered narrative to the understanding of this language syndrome.

Main Methods:

• Retrospective analysis of a large neurosurgical database (n=307).
• Utilized voxel-based and multivariate lesion-symptom mapping (VLSM, MLSM) to identify lesion-symptom correlations.
• Compared lesion locations in patients with the specific language profile to control groups.

Main Results:

• A significant association was found between left dmPFC damage and a language profile affecting self-generated speech production.
• This linguistic disturbance was disproportionately linked to dmPFC resections, with a nearly 15-fold increased probability compared to other brain regions.
• The identified language profile was distinct from motivational or motor speech impairments.

Conclusions:

• Left dmPFC damage can cause a unique linguistic disturbance primarily impacting spontaneous speech.
• This study underscores the critical role of the left dmPFC in the volitional control of fluent, self-generated speech.
• Findings challenge existing language models by incorporating the dmPFC and offer insights from a patient's recovery narrative.