Images of desire: food-craving activation during fMRI Marcia Levin Pelchat, a, * Andrea Johnson, b Robin Chan, c Jeffrey Valdez, c and J. Daniel Ragland c a Monell Chemical Senses Center, Philadelphia, PA 19104-3308, United States b History and Sociology of Science, University of Pennsylvania, Philadelphia, PA 19104, United States c Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104, United States Received 10 May 2004; revised 12 August 2004; accepted 18 August 2004 Food craving (defined as an intense desire to eat a specific food) is of interest because it is extremely common and because it influences obesity or nutritional status. It has also been suggested that food craving may be the evolutionary source for cravings of all kinds including cravings for drugs and alcohol. Yet, little is known about the functional neuroanatomy of food craving. We report here the first functional magnetic resonance imaging (fMRI) study to explicitly examine food craving. A two-part technique was used to produce the food cravings. Threshold was reduced through a diet manipulation (monotonous diet) and cravings were triggered during blood oxygen- ation level-dependent (BOLD) fMRI sessions by having subjects imagine the sensory properties of favorite foods (a cue-induction technique). Subjects were also asked to imagine the monotonous diet (which they did not crave). Diet condition had an activating effect on both behavioral (reports of craving) and fMRI measures. Craving- related changes in fMRI signal were identified in the hippocampus, insula, and caudate, three areas reported to be involved in drug craving. Thus, this work supports the common substrate hypothesis for food and drug cravings. D 2004 Elsevier Inc. All rights reserved. Introduction The most commonly used definition of food craving is that it is an intense desire to eat a specific food (Kozlowski and Wilkinson, 1987; Weingarten and Elston, 1990). There are two aspects of this definition that are important. One is that the desire be intense, something that we might go out of our way for. Intensity distinguishes food cravings from ordinary food choices. The other critical aspect of the definition is specificity. This serves to contrast food craving to hunger: When hungry, any of a wide variety of foods could be satisfying. However, there is a sensory memory or template that must be matched in order to satisfy a craving. Food cravings are of nutritional interest because of their high prevalence and their nutritional impact. Surveys in the United States, Canada, and Great Britain using a definition similar to that described above consistently show that food cravings are extremely common (Pelchat, 1997; Weingarten and Elston, 1991). Close to 100% of young adult females and about 70% of young men report having experienced one or more food cravings at some time in the past year. Food cravings may contribute to obesity and eating disorders. They are widely believed to influence snacking behavior, compliance with dietary restrictions, binge eating, and lifetime prevalence of bulimia nervosa (Basdevant et al., 1993; Gendall and Joyce, 2001; Waters et al., 2001; Wurtman, 1988). There are numerous theories on the basis for food cravings. Probably the most common, especially among laypersons (Wein- garten and Elston, 1991), is that cravings arise in response to a nutrient or caloric deficit. However, it has been surprisingly difficult to demonstrate a relationship between nutritional need and food craving in a laboratory setting (Beauchamp et al., 1990; Weingarten and Elston, 1991). Further, in many cases, nutritional deprivation is confounded with dietary monotony. Pelchat and Schaeffer (2000) found that young adult subjects on a nutritionally adequate, single food, sweet (monotonous) diet (large quantities of a nutritional supplement beverage) experience large increases in food cravings as compared with a baseline (normal diet) period. Therefore, hunger or nutritional need is not a necessary condition for the production of food cravings, and food cravings are clearly a separate phenomenon from hunger. In addition to its bearing on mechanisms for food craving, a nutritionally adequate but monotonous diet was used as a tool to increase the probability of food cravings in this study. Drug craving is viewed as central to maintenance and relapse of drug addiction (American Psychiatric Association, 1994). Thus, a more thorough understanding of craving could contribute to better comprehension of basic processes underlying addiction and to the design of more effective therapeutic interventions. Many lines of evidence suggest that there are similar neural substrates for food and drug rewards (Kelley and Berridge, 2002; Pelchat, 2002; Wise, 1053-8119/$ - see front matter D 2004 Elsevier Inc. All rights reserved. doi:10.1016/j.neuroimage.2004.08.023 * Corresponding author. Monell Chemical Senses Center, 3500 Market Street, Philadelphia, PA 19104-3308. Fax: +1 215 898 2084. E-mail address: pelchat@monell.org (M.L. Pelchat). Available online on ScienceDirect (www.sciencedirect.com.) www.elsevier.com/locate/ynimg NeuroImage 23 (2004) 1486 – 1493