Midbrain response to milkshake correlates with ad libitum milkshake intake in the absence of hunger

Abstract

There is now widespread agreement that individual variation in the neural circuits representing the reinforcing properties of foods may be associated with risk for overeating and obesity. What is currently unknown is how and whether brain response to a food is related to immediate subsequent intake of that food. Here we used functional magnetic resonance imaging (fMRI) to test whether response to a palatable milkshake is associated with subsequent ad libitum milkshake consumption. We predicted that enhanced responses in key reward regions (insula, striatum, midbrain, medial orbitofrontal cortex) and decreased responses in regions implicated in self-control (lateral prefrontal and lateral orbitofrontal cortex) would be associated with greater intake. We found a significant positive association between response to milkshake in the periaqueductal gray region of the midbrain and ad libitum milkshake intake. Although strong bilateral insular responses were observed during consumption of the milkshake this response did not correlate with subsequent intake. The associations observed in the midbrain and orbitofrontal cortex were uninfluenced by ratings of hunger, which were near neutral. We conclude that midbrain response to a palatable food is related to eating in the absence of hunger.

Relative ability of fat and sugar tastes to activate reward, gustatory, and somatosensory regions

“…In contrast, the high-sugar compared with high-fat milkshakes elicited greater activation in the bilateral insula extending into the putamen and the Rolandic operculum and left thalamus. This pattern of findings suggested that tastes of high-fat compared with high-sugar milkshakes prompted greater activation in regions involved in associative learning processes (caudate and hippocampus) and somatosensory regions (postcentral gyrus), whereas tastes of high-sugar compared with high-fat milkshakes prompted greater activation in regions associated with reward and motivation (insula and putamen), oral somatosensation (Rolandic operculum), and gustatory stimulation (thalamus) (24)(25)(26)(27)(28). To our knowledge, these findings make a novel contribution to the literature in that it appears that no previous study has compared the neural response to foods that are high in fat compared with high in sugar, with control for energy density and flavor.…”

A functional neuroimaging review of obesity, appetitive hormones and ingestive behavior

“…Midbrain and medial OFC activity in response to milkshake receipt (small tastes; ∼30 mL over the scanning session) positively predicted subsequent ad libitum milkshake consumption [64]. Of note, this sample included lean and overweight individuals, however BMI was included as a covariate in all analyses.…”

Eating in the absence of hunger in college students

“…This is important to take into consideration because an individual's likelihood to consume food is often influenced by environmental factors, such as the look and smell of hedonic food. Results from the study conducted by Nolan-Poupart et al show that increased activity in the midbrain, more specifically the periaqueductal gray (PAG) region, (p=0.045) and the mOFC (p=0.061) is positively associated with increased ad libitum milkshake consumption (24). This neurologic response to food may be due to metabolic needs and effects, and may vary between individuals.…”

“…Decreased activity in these regions has been shown to be associated with high BMI as well. Further, research has shown that obese individuals have an increased likelihood to have a decreased gray matter density in the lateral prefrontal cortex (24). It has been previously shown that researchers are able to predict an individual's food intake after a meal has been consumed, but these predictions were not made while the subject was exposed to food.…”

“…Varying neuroimaging responses to food have been documented in response to different smells, visual images, and flavors. In addition, neuroimaging responses to food have been documented across different body weights and eating phenotypes (24). The areas in the brain associated with the reward properties of food are the insula/operculum, midbrain, medial orbitofrontal cortex, striatum, and insula.…”