Research has implicated an addictive process in the development and maintenance of obesity. Although parallels in neural functioning between obesity and substance dependence have been found, to our knowledge, no studies have examined the neural correlates of addictive-like eating behavior.
YFAS scores showed positive correlations with activation in the left ACC, left medial OFC, and left amygdala in response to anticipated intake of palatable food. Participants in the High FA group versus the Low FA group showed greater activation in the left DLPFC and right caudate. The High FA group showed less activation in the left lateral OFC during food intake than the Low FA group. FA scores correlated positively with activation in the ACC, medial OFC, and amygdala in response to anticipated intake of palatable food but were not significantly related to activation in response to palatable food intake. High versus low FA participants demonstrated greater activation in the DLPFC and caudate during anticipated palatable food intake and reduced activation in the lateral OFC during palatable food intake. Elevated FA scores were associated with greater activation of regions that play a role in encoding the motivational value of stimuli in response to food cues. The ACC and medial OFC have both been implicated in motivation to feed and to consume drugs among individuals with substance dependence. Elevated ACC activation in response to alcohol-related cues is also associated with reduced D2 receptor availability and increased risk for relapse. Similarly, increased activation in the amygdala is associated with increased appetitive motivation and exposure to foods with greater motivational and incentive value. In addition, the DLPFC is associated with memory, planning, attentional control, and goal-directed behavior. Neural activation of regions that appear to play a role in the encoding of craving was also positively correlated to FA scores. Finally, FA scores were associated with activation in regions that play a role in disinhibition and satiety. The high FA group exhibited patterns of neural activation associated with reduced inhibitory control. The findings suggest that FA is associated with reward-related neural activation that is frequently implicated in substance dependence.
Neural correlates of food addiction
Gearhardt, A. N., Yokum, S., Orr, P. T., Stice, E., Corbin, W. R., & Brownell, K. D.
The aim of the study to examine the relation between FA and neural activation of reward circuitry to intake and anticipated intake of palatable food. At baseline, BMIs were determined, and the Yale Food Addiction Scale (YFAS) was administered. Participants were scanned at baseline. Participants were asked to consume regular meals but to refrain from eating or drinking (including caffeinated beverages) for 4 to 6 hours immediately preceding their imaging session. This deprivation period was selected to capture the hunger state that most individuals experience as they approach their next meal, which is a time when individual differences in food reward would logically impact caloric intake. Most participants completed the paradigm between 10 AM and 1 PM, but a subset completed scans between 2 and 4 PM. Before the imaging session, participants were familiarized with the functional magnetic resonance imaging (MRI) paradigm through practice on a separate computer. The milkshake paradigm was designed to examine brain activation in response to consumption and anticipated consumption of palatable food. Stimuli consisted of 2 images (glass of milkshake and glass of water) that signaled the delivery of either 0.5 ml of a chocolate milkshake or a calorie-free tasteless solution, designed to mimic the natural taste of saliva. Water has a taste that activates the taste cortex. Order of presentation was randomized, and images were presented for 2 seconds using MATLAB f. Taste delivery occurred 5 seconds after onset of the cue and lasted 5 seconds. Each run consisted of 30 events each of milkshake cue and milkshake intake and 20 events each of tasteless solution cue and of tasteless solution intake. Fluids were delivered using programmable syringe pumps. Images were presented with a digital projector/reverse screen display system at the end of the MRI scanner bore, visible via a head coil mounted mirror. Before the scan, participants consumed the milkshake and tasteless solution and rated desire for, perceived pleasantness, edibility, and intensity of the tastes on cross-modal visual analog scales. Individual maps were constructed to compare the activations within each participant for the contrasts and were then regressed against total YFAS scores. Women were tested in the mid-follicular phase (4-8 d after first period) when expected to show greatest response in reward regions compared to those in the luteal phase.
48 young women (Mean = 20.8) with a Mean Body Mass Index (BMI) of 28.0 who enrolled in a program developed to help people achieve and maintain a healthy weight on a long-term basis. Individuals who reported binge eating or compensatory behaviors (e.g., vomiting for weight control), use of psychotropic medications or illicit drugs over the past three months, smoking, head injury with a loss of consciousness, or current (past three months) psychiatric disorder were excluded.
Gearhardt, A. N. (2011). Neural Correlates of Food Addiction. Archives of General Psychiatry, 68(8), 808. doi:10.1001/archgenpsychiatry.2011.32