Neurophysiology of social processing and underlying perceptual deficits in schizophrenia

ABSTRACT Schizophrenia (SZ) is a debilitating and complex disorder with many symptoms, and current treatments often don't address the totality of the illness. One symptom that is often overlooked is social processing deficits, and these difficulties can cause significant functional impairment for these patients. Patients with SZ are also known to have subtle perceptual deficits, and it is possible that these may be related to social processing deficits. More research examining how these social and perceptual processing difficulties manifest in the brain is needed, especially research utilizing naturalistic stimuli that mimic real life. Here, we use episodes of the comedy TV show, The Office, as our stimulus because it contains a rich variety of social interactions, including some that may be violating social norms (i.e., awkward events). These episodes are also rich in speech content that will allow us to examine language at many different hierarchical levels of processing. We will use two complementary neuroimaging imaging modalities to examine social brain network differences in patients with SZ and how more basic perceptual language processing deficits may be influencing these measures. Our analysis will allow us to quantify specific stimulus parameters related to social understanding, like awkwardness, and language processing, such as low-level envelope tracking and higher-level linguistic meaning. We will then quantify how the neural signal reflects these stimulus parameters using linear methods. For Aim 1, we will use functional magnetic resonance imaging (fMRI) techniques to characterize neural dynamics of social and perceptual processing deficits in SZ. We will first assess the neural tracking of language features during the episodes utilizing a general linear model approach (GLM). Next, we will quantify group differences in how the brain tracks with social parameters, like awkwardness. We will also characterize neural dynamics between important nodes in the social processing brain network. For Aim 2 will use electroencephalography (EEG) to characterize neural tracking of speech features with more temporal precision compared to fMRI. We will also examine how social features are reflected in the neural signal and characterize functional connectivity of social processing regions within specific frequency ranges. We predict that across both aims, the brains of patients with SZ will track less with the perceptual and social features of the stimulus, and that any perceptual deficits may be contributing to social deficits. We aim to recruit the same participants for aim 1 and 2, so we can capitalize on the strengths of both methods and examine how these measures may be providing complementary information about language and social processing deficits. We hope that this research can be used to inform future research for biomarkers of SZ and ultimately improve healthcare outcomes for patients with SZ.