46. Effort, Avolition, and Function in Schizophrenia: Analysis of Behavioral and Neuroimaging Data With Relationships to Real-World Function

Abstract

Background: Many schizophrenia (SZ) patients experience negative symptoms such as reductions in motivational drive. Recent work has suggested that abnormal effort-based decision-making may be a key contributory mechanism to such motivational defcits. However, the neural correlates of effort-based decision-making defcits in SZ as well as relationships to real-world functioning are unclear. Method(s): To test this hypothesis about effort-based decision-making, we utilized a novel paradigm. Prior to scanning, participants (30 SZ; 30 CN) experienced increasingly diffcult versions of a cognitively demanding task. Then participants made decisions about repeating diffcult levels for increased reward or an easy level for less reward. Easy version offers were stepwise titrated until an indifference point was reached. Next, during fMRI scanning, participants made choices between repeating hard/easy levels for more or less reward. In addition, to analyze relationships between effort-based decision-making and real-world function participants completed a weeklong ecological momentary assessment protocol. Four times/day subjects completed a short cell phone survey stating their current activities and interest/enjoyment with these activities. Result(s): Patients required greater amounts of money to choose to per-form cognitively demanding tasks compared to CNs. This effect was largest for high negative symptom patients and held even when account-ing for behavioral performance. Analysis of daily reports of emotional experience revealed that patients who showed the greatest effort avoidance also reported the least enjoyment/interest in their daily activities, suggesting that defcits in experimentally derived effort-based decision-making may be linked to real-world emotional functioning. Finally, we hypothesize that brain regions highly implicated in the allocation of effort, as well as representations of subjective value, such as the anterior cingulate cortex, ventromedial prefrontal cortex, and ventral striatum will show blunted activation patterns for SZ patients compared to CN during effort-based decisions, suggesting specifc neural correlates for aberrant choice behavior. Conclusion(s): Our results suggest that abnormal effort-based decision-making may be a contributory mechanism to motivational impairment and is related to real-world function in those with SZ. Such fndings have important implications to the etiology of abnormalities in goal-oriented behavior in SZ.