A specific brain region has been shown to represent our personal beliefs about a food item’s nutritive elements, which can then be used to calculate the food’s personal value, reports a study published online this week in Nature Neuroscience.
The brain region, called the orbitofrontal cortex (OFC), is attributed to representing the expected value of rewards, like food, money, consumer goods, and enjoyable activities, when we need to make a decision between different options. However, it is currently unclear how these ‘value signals’ are built in the brain.
Shinsuke Suzuki and colleagues focused on valuation of food rewards, measuring neural activity with functional magnetic resonance imaging (fMRI) as 23 participants reported their willingness to pay for presented food items, which served as a proxy for each food’s personal value. After scanning, participants provided their estimates on the amounts of fat, sodium, carbohydrate, sugar, protein, and vitamin within each of the food items, as well as their estimated caloric content.
The authors determined that participants’ personal food values were best predicted by their beliefs about the food’s fat, carbohydrate, protein, and vitamin content, rather than objective measures of these elements or estimates of caloric content. Overall personal food value was represented in both the medial and lateral portions of the OFC, but the neural representations of personal beliefs about the fat, carbohydrate, protein, and vitamin content were located only in the lateral OFC. Each of these elements were represented by distinct patterns of activity within the lateral OFC, and were observed specifically as participants viewed and assigned values to food items before indicating the amount they wanted to pay for them. During this ‘valuation’ period, connectivity between medial OFC and the lateral OFC subregions that encoded each of the four subjective food elements increased, which suggests that the medial OFC might integrate the element-specific signals from the lateral OFC to compute subjective values for food.