Imaging of brain dopamine pathways: implications for understanding obesity

Area of Science:

• Neuroscience
• Psychiatry
• Metabolic Disorders

Background:

• Obesity is associated with abnormal eating behaviors.
• Dopamine (DA)-modulated circuits are implicated in pathologic eating.
• Food cues affect brain regions involved in motivation and reward.

Purpose of the Study:

• To investigate the role of dopamine circuits in the eating behaviors of obese individuals.
• To compare brain activity in obese subjects with that of drug-addicted individuals.

Main Methods:

• Brain imaging studies in humans.
• Measurement of dopamine D2 receptor availability.
• Assessment of brain metabolism in response to food cues and gastric stimulation.

Main Results:

• Obese subjects show reduced striatal DA D2 receptor availability.
• Decreased DA D2 receptors correlate with reduced metabolism in prefrontal inhibitory control regions.
• Obese subjects exhibit increased metabolism in the somatosensory cortex, indicating heightened sensitivity to food.
• Brain regions activated by gastric stimulation in obese individuals overlap with those activated during drug craving.

Conclusions:

• Disruptions in brain circuits, particularly involving dopamine, are similar in obesity and drug addiction.
• Reduced DA D2 receptors and enhanced sensitivity to food may lead to compulsive eating.
• Strategies targeting dopamine function could aid in obesity treatment and prevention.