Entries in orbital frontal cortex (1)

Friday
Dec222017

How Does Our Brain Assign Value to Food?

Fig. 1: Schematic representation of how our brain incorporates perception of food items into willingness to pay [ref 3].How do we decide what and how much to eat and how much we are willing to pay for food? We may think about these questions sometimes, but apparently, our brains actually “compute” food values when we make decisions about what to eat. These value signals have been found to possess regional specificity and recent research demonstrates that sub-regions within the orbitofrontal cortex (OFC), play unique roles [1]. The OFC is involved in higher-order cognitive functions such as decision-making and human brain imaging studies have begun to illustrate functional contributions of the OFC in food value computation. For example, several studies have indicated that the medial OFC encodes generalized value signals, independent of direct experience or consideration of future rewards, while the lateral OFC encodes specific value [2].

Recent work has elucidated the “constituent attributes” that underlie the construction of food value and how they are both represented and integrated in the OFC [1]. By using a food-based decision task in human participants, researchers found that a subjective sense of nutrients are important in assigning value to food; nutritive aspects of our food, such as protein, fat, carbohydrates and vitamins, appear to be important predictors of the subjective value of food. Multi-voxel pattern analyses (MVPA) of functional magnetic resonance imaging (fMRI) data revealed that both the medial and lateral OFC represent food value signals with the lateral OFC encoding for the basic nutritional aspects of food. The results of effective connectivity analyses between OFC sub-regions indicated that information in relation to subjective nutrient factors from the lateral OFC are then integrated at the time of valuation within the medial OFC, which “computes” overall values. More simply, the lateral OFC estimates the amount of nutrients and the medial OFC works out a weighted sum value, influencing behavior.

Understanding how a subjective value signal is generated in the lateral OFC and how inter-regional signals relate to more involved network representations remains elusive, yet these studies provide new data for further study with important implications for understanding neural and psychological mechanisms underlying food-valuation processes, salient for diseases in which these processes are out of balance, such as in eating disorders [1]. Further, these studies represent a conceptual advance which may eventually be generalized to other value judgments [3].

-YTC

 

References

1. Suzuki, S.; Cross, L.; O’Doherty, J. P., Elucidating the underlying components of food valuation in the human orbitofrontal cortex. Nat. Neurosci. 2017, 20 (12), 1780-1786.

2. (a) Barron, H. C.; Dolan, R. J.; Behrens, T. E. J., Online evaluation of novel choices by simultaneous representation of multiple memories. Nat. Neurosci. 2013, 16 (10), 1492-1498 ; (b) Howard, J. D.; Gottfried, J. A.; Tobler, P. N.; Kahnt, T., Identity-specific coding of future rewards in the human orbitofrontal cortex. Proceedings of the National Academy of Sciences of the United States of America 2015, 112 (16), 5195-5200.

3. Pessiglione, M.; Wiehler, A., Breaking down a meal. Nat. Neurosci. 2017, 20 (12), 1659-1660.