Lesion-Induced Changes to the Network Controllability of the Right Pars Triangularis in Aphasia

Area of Science:

• Neuroscience
• Neurolinguistics
• Network Science

Background:

• Left hemisphere stroke can disrupt language networks, potentially leading to right hemisphere recruitment.
• The role of the right pars triangularis (rPTr) in language processing post-stroke is debated, with mixed evidence on its functional significance and response to neuromodulation.
• White matter connectivity may mediate the effects of stroke on language network function.

Purpose of the Study:

• To investigate if left hemisphere stroke alters the structural topological properties of the right pars triangularis (rPTr).
• To examine the relationship between the rPTr's network control properties and language processing in persons with aphasia (PWA).

Main Methods:

• Utilized network control theory (NCT) measures, specifically boundary controllability (BC), to assess the rPTr's communication integration capacity.
• Compared BC in the rPTr between 60 PWA and 62 controls.
• Correlated rPTr BC with semantic and phonological language performance in PWA.

Main Results:

• Persons with aphasia (PWA) exhibited significantly higher boundary controllability (BC) in the right pars triangularis (rPTr) compared to controls.
• Higher rPTr BC was associated with a reduction in phonological errors during a picture naming task.

Conclusions:

• Left hemisphere stroke induces changes in the structural network control properties of right hemisphere regions, including the rPTr.
• The increased BC in the rPTr in PWA may reflect a compensatory mechanism for language processing deficits.
• These findings highlight the importance of structural connectivity in understanding post-stroke language recovery and the role of right hemisphere regions.