Ghrelin Boosts Brain's Response to Pictures of Food
Hormone, which boosts food consumption, may promote eating by enhancing pleasure of food
WEDNESDAY, May 7 (HealthDay News) -- Ghrelin, a gut peptide hormone that triggers hunger and food consumption, may promote eating by increasing the hedonic and incentive responses to food-related cues, according to research published in the May 7 issue of Cell Metabolism.
Saima Malik, of McGill University in Montreal, Quebec, Canada, and colleagues analyzed data from 20 healthy, non-obese young adult males. During functional MRI, 12 subjects viewed pictures of foods and scenery before and after single-blinded ghrelin administration, and the rest viewed the same pictures without ghrelin.
Ghrelin increased the neural response to pictures of food in subjects' amygdala, orbitofrontal cortex, insula, visual areas and striatum, the researchers report. These areas are involved in encoding the incentive value of food cues, as well as reward processing and appetitive behavior. In addition, self-reported hunger was increased in the ghrelin group and correlated positively with the ghrelin-related increase in activity in the amygdala, orbitofrontal cortex and pulvinar.
"Ghrelin therefore appears to modulate the response to food cues of a neural network involved in the regulation of feeding and, most importantly, in the appetitive response to food cues. This appetitive response has several components: attention, anticipation of pleasure, motivation to eat (hunger), consumption, and memory for associated cues. Brain regions implicated in all of these functions were modulated by ghrelin. How ghrelin acts on the brain is not known, but several potential mechanisms have been identified," the authors write.