Hunger is the best spice: An fMRI study of the effects of attention, hunger and calorie content on food reward processing in the amygdala and orbitofrontal cortex

Abstract

Research indicates that dysfunctional food reward processing may contribute to pathological eating behaviour. It is widely recognized that both the amygdala and the orbitofrontal cortex (OFC) are essential parts of the brain's reward circuitry. The aims of this fMRI study were (1) to examine the effects of food deprivation and calorie content on reward processing in the amygdala and the OFC, and (2) to examine whether an explicit evaluation of foods is necessary for OFC, but not amygdalar activity. Addressing the first aim, healthy females were presented with high and low calorie food pictures while being either hungry or satiated. For the second aim, attention focus was manipulated by directing participants' attention either to the food or to a neutral aspect. This study shows that hunger interacts with the energy content of foods, modulating activity in the posterior cingulate cortex, medial OFC, insula, caudate putamen and fusiform gyrus. Results show that satiated healthy females show an increased reward processing in response to low calorie foods. Confirming our hypothesis, food deprivation increased activity following the presentation of high calorie foods, which may explain why treatments of obesity energy restricting diets often are unsuccessful. Interestingly, activity in both the amygdala and mOFC was only evident when participants explicitly evaluated foods. However, attention independent activity was found in the mPFC following the high calorie foods cues when participants where hungry. Current findings indicate that research on how attention modulates food reward processing might prove especially insightful in the study of the neural substrates of healthy and pathological eating behaviour.

Neural Responses to BEGIN- and END-Stimuli of the Smoking Ritual in Nonsmokers, Nondeprived Smokers, and Deprived Smokers

“…In contrast, in a deprived state mainly stimuli predicting a prospective availability lead to the strongest activations. Similar effects were found in a study on food deprivation (Siep et al, 2009); subjects saw pictures of high-or low-calorie food while being either hungry or satiated. The results revealed an increased reward processing in response to low-calorie food in satiated subjects but in response to high calorie food in deprived subjects.…”

Reward activity in satiated overweight women is decreased during unbiased viewing but increased when imagining taste: an event-related fMRI study

“…For food-reward-related activity to occur in lean individuals, attention to food seems to be necessary, more specifically: the evaluation or imagination of its taste. This was shown by an earlier study from our laboratory 23 in healthy-weight participants after food deprivation and during satiation; this study found that the orbitofrontal cortex (OFC) and the amygdala, both involved in encoding the predictive reward value of stimuli, 24,25 were activated only during taste imagination of high-calorie and low-calorie food pictures and not when judging the orientation of bars presented together with the foods. Likewise, activation of the left lateral OFC in healthy participants depended on whether or not a taste was explicitly evaluated.…”

The benefits of simply observing: Mindful attention modulates the link between motivation and behavior.

“…When hungry, one is likely to retrieve especially rewarding simulations (based on earlier, highly rewarding eating experiences), in contrast to retrieving less rewarding simulations when satiated. Consistent with this account, research has repeatedly shown that food deprivation and feeling hungry increase reward responses to food, especially to high-calorie food, both in behavioral and neuroimaging studies (Berridge, 1996;Cabanac, 1971;Lavy & van den Hout, 1993;Lozano, Crites, & Aikman, 1999;Raynor & Epstein, 2003;Seibt et al, 2007;Siep et al, 2009;van der Laan, de Ridder, Viergever, & Smeets, 2011). In short, by triggering more rewarding simulations, hunger boosts the perceived attractiveness and choices of palatable, high-calorie foods.…”