Positive emotion and emotional eating

Emotional eating is a phenomenon in which a person consumes food for reasons other than being physically hungry. Because emotional eating is significantly related to clinical eating disorders like bulimia and binge eating disorder, as well as obesity and malnutrition, there is growing interest in learning how to treat and prevent the issue. More specifically emotional eating is linked to a tendency to overeat in response to negative emotions, but little is known about emotional eating and positive emotions – like happiness or excitement. A team of researchers decides to study the relationship between positive emotion and emotional eating.

The researchers recruit $5$‍ women who have expressed having issues with emotional eating. For two days, the women report to a lab that is full of their favorite foods, and are told to consume as much as they desire. On day one, each participant is exposed to a thirty-minute situation that should induce sadness or anxiety (like a tragic news article or movie). On day two, each participant is exposed to a situation that should induce happiness or excitement (like spontaneously winning a substantial prize). Their heart rate and blood pressure serve as physiological measurements of their excitement pre-and post- each emotion induction scenario, and the number of calories they consume over the thirty minutes is recorded as a measure of emotional eating. Each participant's caloric intake is outlined in Table $1$‍.

Which of the following structures plays a key role in emotional expression?