Deciphering Amotivation in Schizophrenia: A Bayesian Computational Analysis of Exploratory Behavior

Poster Session D - Monday, April 15, 2024, 8:00 – 10:00 am EDT, Sheraton Hall ABC

Yi Yang^1,2 (jasonyiyang.yang@mail.utoronto.ca), Povilas Karvelis², Ishraq Siddiqui³, George Foussias^1,3,4, Andreea Diaconescu^1,2,4; ¹Institute of Medical Science, University of Toronto, Toronto, Canada, ²Krembil Centre for Neuroinformatics, Centre for Addiction and Mental Health, Toronto, Canada, ³Schizophrenia Division and Campbell Family Research Institute, Centre for Addiction and Mental Health, Toronto, Canada, ⁴Department of Psychiatry, University of Toronto, Toronto, Canada

Amotivation significantly influences functional outcomes in schizophrenia (SZ), yet its etiological pathways and effective treatments remain elusive. This study builds upon the virtual exploration work in SZ from Siddiqui et al., by applying a Bayesian computational framework to dissect the components associated with amotivation in SZ. We examined 24 outpatients with SZ and 26 controls who completed the Virtual Novelty Exploratory Task, which involves first-person perspective exploration of a simulated city environment. Our behavioral analysis of task performance investigated group differences and relationships with clinical rating measures of amotivation. Then, we employed a 3-level Hierarchical Gaussian Filter model to the behavioral data and evaluated model parameters based on group differences and relationships with clinical amotivation. Our behavioral analysis found that amotivation was correlated with “Exploratory-Walking” behavior (p=0.004, r=-0.56). “Scanning-Environment” behavior was also reduced in the SZ group (p=0.025). From a computational perspective, the SZ group exhibited an increase in the phasic component of the learning rate (kappa; p=0.005). Further, SZ patients’ amotivation was correlated with model parameters that represented uncertainty reduction response (β_2; p=0.006, r=0.54) and prior-about-novelty (μ_2^(k=0); p=0.009, r=-0.52). Our findings offer empirical support for the aberrant salience hypothesis and highlight underlying cognitive processes associated with amotivation in SZ. Specifically, patients with SZ appear to experience increased uncertainty in their world perception as they assimilate more information (kappa). Additionally, patients with more severe motivation deficits appear to demonstrate a reduced inclination to minimize uncertainty through exploration (β_2) and perceive their environment as being less novel (μ_2^(k=0)).

Topic Area: THINKING: Decision making