Neural Activation During Cognitive Effort-Based Decision Making: Associations With Avolition in Veterans With Schizophrenia and Bipolar Disorder.

BACKGROUND

Effort-based decision making (EBDM) is a key component of motivation. Impairments in EBDM have been consistently linked to amotivation in individuals with schizophrenia (SZ). Similar deficits are seen in SZ and bipolar disorder (BD), despite striking differences in motivational profiles between the two disorders. Similar task behavior, but distinct motivational profiles, may arise from functional differences in brain regions supporting EBDM.

METHODS

Twenty-eight veterans with SZ, 21 veterans with BD, and 30 healthy control participants completed a cognitive EBDM task during functional magnetic resonance imaging scanning. Participants chose between an easy and a more effortful working memory task. Reward values were manipulated to bias the participant toward choosing the more effortful task or the easier task or were relatively unbiased.

RESULTS

Participants with SZ spent less time deliberating on unbiased trials and exhibited reduced task-related activation in the anterior cingulate cortex (ACC), anterior insula, and dorsolateral prefrontal cortex compared with participants in the healthy control and BD groups. Greater activation to hard-task biased trials relative to unbiased or biased toward easy task trials in the striatum, ventromedial prefrontal cortex, and posterior cingulate cortex was associated with motivation deficits in SZ but lower amotivation in BD.

CONCLUSIONS

Hypoactivation in response to the task in the ACC and other regions was found in the SZ group. Associations found between activation in several brain regions underlying EBDM and clinical amotivation suggest that distinct neurobehavioral processes contribute to motivational deficits in SZ and BD.