A new study conducted by researchers at University of British Columbia looks into why we are not affected by enticing pictures of food when we are full.
"We've known that insulin plays a role in telling us we're satiated after eating, but the mechanism by which this happens is unclear," said Stephanie Borgland, an assistant professor in UBC's Dept. of Anesthesiology, Pharmacology and Therapeutics and the study's senior author.
In the new study, Borgland and colleagues found that insulin - prompted by a sweetened, high-fat meal - affects the ventral tegmental area (VTA) of the brain, which is responsible for reward-seeking behaviour. When insulin was applied to the VTA in mice, they no longer gravitated towards environments where food had been offered.
"Insulin dulls the synapses in this region of the brain and decreases our interest in seeking out food," said Borgland, "which in turn causes us to pay less attention to food-related cues."
"This study helps explain why pictures or other cues of food affect us less when we're satiated - and may help inform strategies to reduce environmental triggers of overeating," the researcher added.
The VTA has also been shown to be associated with addictive behaviours, including illicit drug use.
Borgland noted that better understanding of the mechanism in this region of the brain could, in the long run, inform diagnosis and treatment.
The study has been published online this week in Nature Neuroscience.