Emily Przysinda - PhD Candidate, Advisors: Ed Lalor & David Dodell-Feder
One often overlooked symptom of schizophrenia (SCZ) is marked and persistent difficulties with social information processing. Since social interactions hinge upon understanding our external environment, it’s possible that known language deficits in SCZ could contribute to social difficulties. Here, we aim to understand the neural basis for social deficits and potential underlying language processing deficits in SCZ while participants view naturalistic video stimuli. We examine differences between SCZ patients and neurotypical controls (NTC) using complementary neuroimaging methods, fMRI and EEG, in separate studies with mostly overlapping participants.
For study 1, we chose to focus on a network of brain regions supporting a subset of social processing, theory of mind (ToM), as previous research has shown ToM deficits in SCZ. The fMRI analysis revealed between group differences in the extent to which ToM brain regions were engaged during socially awkward events. Specifically, the SCZ group showed reduced recruitment of the dorsal medial prefrontal cortex (mPFC) compared to controls. Using graph theory methods, we also found a prominent decrease in global efficiency in the dorsal and middle mPFC for SCZ compared to NTC. Our findings converge with previous literature showing decreased functional connectivity during explicit ToM tasks in SCZ, and here we show here that these findings can be replicated in a more naturalistic paradigm. Analysis of these same ToM regions using EEG in study 2 allows us to discern fluctuations in connectivity between ToM regions that may be sensitive to different aspects of the neural signal compared to fMRI.
For study 3, we used linear methods to relate the EEG signal to the auditory and language features of the episode, which yields quantitative values that index how well the brain is tracking these features. We found that EEG tracking of acoustic envelope and lexical surprisal was reduced in SCZ versus NTC. This suggests that patients with SCZ may have difficulty in processing basic acoustic and language features of naturalistic video. The overlap of subjects between these studies allows us to make within-subject comparisons of both language and social processing measures, while also capitalizing on the strengths of both neuroimaging methods.
Nov 09, 2023 @ 12:00 p.m.
Medical Center | Ryan Case Method Rm (1-9576)