What: Neural mechanisms of sentence processing and dynamics of its recovery in aphasia: a multimodal neuroimaging perspective.
Where: Zoom Room 1
Who: Elena Barbieri, PhD., Research Associate, Center for the Neurobiology of Language Recovery, Northwestern University, Chicago, IL, US.
When: 2 PM.
According to current neurocognitive models of sentence processing, sentence comprehension and production rely on a network of left-hemisphere regions that includes inferior frontal, posterior temporal and inferior parietal regions. These regions are assumed to support mechanisms such as phrase structure building, thematic mapping and thematic integration, which are crucial for processing syntactically complex sentences (such as passive sentences, e.g. The man was greeted by the girl). Difficulties in production and comprehension of syntactically complex sentences are a hallmark of agrammatic aphasia, an acquired language disorder that most commonly results from stroke, but can also occur as part of a neurodegenerative disease (as in the agrammatic variant of Primary Progressive Aphasia, or PPA-G). In this talk, I will present evidence – derived from functional neuroimaging studies with healthy participants and from volumetric studies in participants with aphasia – that processing of syntactically complex sentences relies on both inferior frontal and posterior temporal/inferior parietal regions in the left hemisphere. Then, I will focus on data showing that participants with stroke-induced agrammatic aphasia primarily activate right hemisphere regions during comprehension of syntactically complex sentences. I will argue that whereas, in the absence of language domain-specific treatment, reliance on right hemisphere resources may be detrimental to recovery, adaptive neuroplasticity in right-hemisphere inferior frontal and posterior temporal regions may occur following treatment for sentence production and comprehension deficits. Finally, I will discuss sentence processing impairments in Primary Progressive Aphasia and its similarities with those exhibited by individuals with stroke-induced aphasia.