Physiol Behav. 2009 July 14; 97(5): 537–550. doi:10.1016/j.physbeh.2009.02.044. # ‘Liking’ and ‘wanting’ food rewards: Brain substrates and roles in eating disorders Kent C. Berridge Department of Psychology, University of Michigan, Ann Arbor, United States ## Abstract What brain reward systems mediate motivational ‘wanting’ and hedonic ‘liking’ for food rewards? And what roles do those systems play in eating disorders? This article surveys recent findings regarding brain mechanisms of hedonic ‘liking’, such as the existence of cubic-millimeter hedonic hotspots in nucleus accumbens and ventral pallidum for opioid amplification of sensory pleasure. It also considers brain ‘wanting’ or incentive salience systems important to appetite, such as mesolimbic dopamine systems and opioid motivation circuits that extend beyond the hedonic hotspots. Finally, it considers some potential ways in which ‘wanting’ and ‘liking’ might relate to eating disorders. ## Keywords Reward; Food; Ingestive behavior; Pleasure; Anorexia; Bulimia; Eating disorders; Nucleus accumbens; Ventral pallidum; Brainstem; Parabrachial nucleus; Dopamine; Opioid; Addiction ### 1. Introduction Obesity, bulimia, anorexia, and related eating disorders have become more prominent in recent decades, leading to increased concern about how to deal with them. Can improved knowledge about brain reward systems help guide thinking about eating disorders and devising better treatments? Basic brain systems for food reward carry potential implications for understanding normal eating and eating disorders. It is important to note first that brain reward systems are active participants, not just passive conduits, in the act of eating. The pleasure of sweetness arises within the brain, generated actively by neural systems that paint the pleasure onto the sensation to generate a 'liking' reaction — as a sort of 'pleasure gloss'. We may be used to thinking of sweet tastes as innately pleasant, but their pleasure is not contained in the intrinsic detail of their sensation but rather in their evolved ability to act as keys that unlock activation of brain 'liking' systems $ [1-3] $ . This is evident by considering that if the ability to unlock hedonic brain systems is lost, a sweet taste loses its pleasure while remaining sweet as ever. For example, a particular sweet taste can become perceived as disgusting rather than nice when an individual learns a taste aversion for it after pairing with visceral illness $ [3-6] $ . Conversely, bitterness activates brain systems of aversion and disgust to be innately aversive, but tastes of cranberries, coffee, beer, ginPhysiol Behav. 2009 July 14; 97(5): 537–550. doi:10.1016/j.physbeh.2009.02.044. # ‘Liking’ and ‘wanting’ food rewards: Brain substrates and roles in eating disorders Kent C. Berridge Department of Psychology, University of Michigan, Ann Arbor, United States ## Abstract What brain reward systems mediate motivational ‘wanting’ and hedonic ‘liking’ for food rewards? And what roles do those systems play in eating disorders? This article surveys recent findings regarding brain mechanisms of hedonic ‘liking’, such as the existence of cubic-millimeter hedonic hotspots in nucleus accumbens and ventral pallidum for opioid amplification of sensory pleasure. It also considers brain ‘wanting’ or incentive salience systems important to appetite, such as mesolimbic dopamine systems and opioid motivation circuits that extend beyond the hedonic hotspots. Finally, it considers some potential ways in which ‘wanting’ and ‘liking’ might relate to eating disorders. ## Keywords Reward; Food; Ingestive behavior; Pleasure; Anorexia; Bulimia; Eating disorders; Nucleus accumbens; Ventral pallidum; Brainstem; Parabrachial nucleus; Dopamine; Opioid; Addiction ### 1. Introduction Obesity, bulimia, anorexia, and related eating disorders have become more prominent in recent decades, leading to increased concern about how to deal with them. Can improved knowledge about brain reward systems help guide thinking about eating disorders and devising better treatments? Basic brain systems for food reward carry potential implications for understanding normal eating and eating disorders. It is important to note first that brain reward systems are active participants, not just passive conduits, in the act of eating. The pleasure of sweetness arises within the brain, generated actively by neural systems that paint the pleasure onto the sensation to generate a 'liking' reaction — as a sort of 'pleasure gloss'. We may be used to thinking of sweet tastes as innately pleasant, but their pleasure is not contained in the intrinsic detail of their sensation but rather in their evolved ability to act as keys that unlock activation of brain 'liking' systems $ [1-3] $ . This is evident by considering that if the ability to unlock hedonic brain systems is lost, a sweet taste loses its pleasure while remaining sweet as ever. For example, a particular sweet taste can become perceived as disgusting rather than nice when an individual learns a taste aversion for it after pairing with visceral illness $ [3-6] $ . Conversely, bitterness activates brain systems of aversion and disgust to be innately aversive, but tastes of cranberries, coffee, beer, gin