The tempted brain eats: Pleasure and desire circuits in obesity and eating disorders

Abstract

What we eat, when and how much, all are influenced by brain reward mechanisms that generate 'liking' and 'wanting' for foods. As a corollary, dysfunction in reward circuits might contribute to the recent rise of obesity and eating disorders. Here we assess brain mechanisms known to generate 'liking' and 'wanting' for foods, and evaluate their interaction with regulatory mechanisms of hunger and satiety, relevant to clinical issues. 'Liking' mechanisms include hedonic circuits that connect together cubic-millimeter hotspots in forebrain limbic structures such as nucleus accumbens and ventral pallidum (where opioid/endocannabinoid/orexin signals can amplify sensory pleasure). 'Wanting' mechanisms include larger opioid networks in nucleus accumbens, striatum, and amygdala that extend beyond the hedonic hotspots, as well as mesolimbic dopamine systems, and corticolimbic glutamate signals that interact with those systems. We focus on ways in which these brain reward circuits might participate in obesity or in eating disorders.

Selective Insulin Resistance in Homeostatic and Cognitive Control Brain Areas in Overweight and Obese Adults

“…Although liking is a hedonic or affective reaction, wanting is important for the motivational aspects (incentive salience) of food reward (38). Even though we observed no sex effects on brain insulin action, we found in lean men only a significant reduction for the wanting of sweet foods after insulin application.…”

Anorexia Nervosa and Obesity are Associated with Opposite Brain Reward Response

“…Those regions are part of the taste reward system: gustatory inputs from the tongue, immediately after food contact, and before gut involvement, project via brain stem and thalamus to the primary taste cortex comprised of insula and frontal operculum, and from there to the ventral striatum and amygdala, and subsequently to hypothalamus, midbrain, and prefrontal cortex (Carmichael and Price, 1996). In this reward circuitry, DA acts as an important learning signal released in response to unexpected stimuli, but it also drives the motivation to approach food and other rewards, called 'wanting' (Berridge et al, 2010). The same neural pathways that reinforce those natural appetitive behaviors are also activated in response to addictive drugs (Hyman and Malenka, 2001).…”

Impulsive consumption and reflexive thought: Nudging ethical consumer behavior

“…Only those consumption goods closely related to strong and salient need deprivation states that activate the brain's mesolimbic dopamine system are appropriate objects for cue-triggered 'wanting'. Deprivation states previously shown to induce cue-triggered 'wanting' include the sexual drive (Dai et al, 2010), the need to eat (Berridge et al, 2010), and the craving for drugs Berridge, 1993, 2008). All of these need deprivation states correspond to activation in the mesolimbic dopamine system.…”