Neural mechanisms underlying hyperphagia in Prader-Willi syndrome

Area of Science:

• Neuroscience
• Genetics
• Metabolic Disorders

Background:

• Prader-Willi syndrome (PWS) is a genetic disorder characterized by developmental delay, obesity, and insatiable hunger (hyperphagia).
• Understanding the neural basis of hyperphagia in PWS may illuminate general mechanisms of overeating and obesity.

Purpose of the Study:

• To investigate the neural mechanisms underlying responses to visual food stimuli in individuals with PWS compared to healthy controls.
• To examine how these neural responses change before and after a meal.

Main Methods:

• Functional magnetic resonance imaging (fMRI) was used to scan participants.
• Participants were scanned in both pre-meal and post-meal conditions.
• Visual stimuli included food, animals, and control images presented in a block design.

Main Results:

• Healthy weight controls (HWC) showed greater activation to food stimuli pre-meal in areas like the amygdala and orbitofrontal cortex.
• Individuals with PWS exhibited greater activation to food stimuli post-meal in regions including the orbitofrontal cortex, insula, and hippocampus.
• PWS group showed heightened activation in food motivation networks after eating compared to HWC.

Conclusions:

• Distinct neural mechanisms underlie hyperphagia in PWS.
• Post-meal hyperactivation in limbic and paralimbic regions (e.g., amygdala) and inhibitory regions (e.g., medial PFC) in PWS suggests complex regulation of eating behavior.