Dopamine Transporter and Reward Anticipation in a Dimensional Perspective: A Multimodal Brain Imaging Study

Area of Science:

• Neuroscience
• Psychiatry
• Neuroimaging

Background:

• Dopamine function and reward processing are interconnected, involving the mesolimbic pathway.
• Impairments in dopamine function and reward systems are common in psychiatric disorders, but the underlying mechanisms remain unclear.
• The relationship between dopamine system variations and reward processing across health and illness is not well understood.

Purpose of the Study:

• To investigate the relationship between dopamine transporter (DAT) availability and neural activity during reward anticipation.
• To explore this relationship across a spectrum of mental health, including healthy volunteers and patients with schizophrenia, depression, and cocaine addiction.

Main Methods:

• Utilized multimodal imaging: positron emission tomography (PET) with [11C]PE2I to assess DAT availability and functional magnetic resonance imaging (fMRI) with a Monetary Incentive Delay task.
• Employed a voxel-based statistical approach on data from 27 participants.
• Examined dopamine transporter availability in the midbrain and reward anticipation response in the nucleus accumbens.

Main Results:

• A significant positive correlation was found between midbrain DAT availability and the neural response to reward anticipation in the nucleus accumbens across all participants.
• This relationship was consistently observed within each clinical subgroup (schizophrenia, depression, cocaine addiction) and healthy controls.
• This study provides the first direct evidence linking DAT availability to reward anticipation within the mesolimbic pathway.

Conclusions:

• Dopaminergic dysfunction, specifically related to DAT availability, is a shared neurobiological mechanism underlying altered reward processing in various psychiatric conditions.
• Findings support a dimensional approach to psychiatry, like the Research Domain Criteria project, for identifying core neurobiological signatures of mental illness.
• The results highlight the importance of the dopamine system in reward processing across the health-illness continuum.