Ventral Striatal Activation During Reward Processing in Psychosis: A Neurofunctional Meta-Analysis

Area of Science:

• Neuroscience
• Psychiatry
• Neuroimaging

Background:

• Abnormal reward processing, potentially linked to ventral striatal (VS) dopamine levels, is implicated in psychotic symptoms.
• Existing functional magnetic resonance imaging (fMRI) studies show inconsistent findings regarding VS activity during reward processing in psychosis spectrum disorders.

Purpose of the Study:

• To systematically assess differences in VS activation during reward processing between patients with schizophrenia spectrum disorders and healthy controls.

Main Methods:

• A comprehensive meta-analysis of fMRI studies published until July 2015, sourced from the Web of Knowledge database.
• Inclusion criteria focused on studies comparing VS activity during monetary reward tasks in patients (schizophrenia spectrum, high-risk) and healthy controls.
• Employed MetaNSUE, a random-effects model, to enable unbiased inclusion of non-statistically significant findings.

Main Results:

• Significant bilateral VS hypoactivation was observed in patients during reward anticipation (23 studies, n=917) and reward feedback (9 studies, n=358).
• Left VS hypoactivation during reward anticipation correlated with higher negative symptom scores in patients (r=-0.41, P<.001).
• The MetaNSUE method demonstrated unbiased effect size estimations, unlike traditional methods that are prone to bias from unreported non-significant findings.

Conclusions:

• This meta-analysis provides robust evidence for VS hypoactivation during reward anticipation in patients with psychosis.
• VS hypoactivation is associated with negative symptoms, suggesting its relevance in the pathophysiology of psychosis.
• Further research on VS prediction errors is warranted to advance understanding and potential interventions.