Orbitofrontal cortex volume and brain reward response in obesity

Area of Science:

• Neuroscience
• Obesity Research
• Brain Imaging

Background:

• Overconsumption of food in obesity is poorly understood.
• Brain structure and function alterations may drive increased food seeking.
• Orbitofrontal cortex (OFC) volume is implicated in dysregulated eating, but its relation to function is unclear.

Purpose of the Study:

• To investigate the relationship between orbitofrontal cortex (OFC) volume and brain reward circuitry activation.
• To compare brain structure and function in obese versus healthy-weight women using multimodal imaging.

Main Methods:

• Multimodal brain imaging (MRI, DTI) in obese (n=18) and control (n=24) women.
• Assessed gray/white matter volume and white matter integrity.
• Tested if OFC volume predicts reward circuitry activation in a taste reinforcement-learning task.

Main Results:

• Obese women had lower gray and white matter volumes in the OFC, striatum, and insula.
• Reduced white matter integrity was observed in obese individuals.
• Medial OFC gray matter volume predicted taste reward-learning activation in controls, but not in obese women.

Conclusions:

• A strong association exists between medial OFC volume and taste reward-learning activation in controls, absent in obese women.
• Reduced brain volumes and white matter integrity in obesity may indicate widespread reward pathway disruption.
• Medial OFC dysfunction could contribute to overconsumption in obesity.