Obesity and addiction have been increasingly detrimental health conditions affecting the American people. Can these diseases be solved by simple verbal cues which trigger top-down processing in the brain to lead to more healthy/abstinent choices? A study by Hare et al found that, indeed, they can. The ventromedial prefrontal cortex (VMPFC), the inferior frontal gyrus (IFC) and the dorsolateral prefrontal cortex (DLPFC) are three brain regions that have been implicated in behavioral choices and decision making. Will the influence of health cues on self-control processes impact decision making in a more healthy and positive way?
Hare hypothesized that dietary choices will be improved by engaging the self-control processes in the DLPFC and IFG and that these choices will be affected by the value signals of the VMPFC, enhanced by the health attributes put into light during the experiment. Subjects were given four types of food to choose from, ranked healthy-tasty, healthy-untasty, unhealthy-tasty and unhealthy-untasty. It was insinuated before the decision making process that the subjects should either make a choice based on health factors or tastiness. fMRIs were used to observe the neural mechanisms at work during decision making. The study yielded a positive correlation between the VMPFC and the subjective stimulus value of each food option.
To understand the works at the neural level, let us find out what role the DLPFC plays in this cascade. The DLFPC has two regions, one, the DLFPC-M, guides the subject to make a healthy decision no matter what. This goal to be healthy is reenergized by health cues which in turn jumpstart a cascade of top-down control processes which govern decision making. The DLPFC-U however, is meant to take into consideration task instructions and to make a decision based on what the individual prefers regardless of the attribute values associated with them. These two areas of the brain come into conflict during this task. When the subjects were told to pick tasty foods, the DLPFC-M M signals to the IFG, which signals to the VMPFC to put more emphasis on the health attributes during decision time. In conclusion, health cues rendered the healthiness of food more important in the VMPFC and increased the likelihood that subjects will behaviorally pick the healthy-untasty food option.
This experiment proves that self-control processes in the DLPFC and IFG triggered by health cues are active during dietary choice and increase the subjective stimulus value of an item in the VMPFC, hence biasing behavioral choice. This study can be incorporated when developing treatments for obesity and addiction.