studying-food-reward-and-motivation-in-humans

Studying Food Reward and Motivation in Humans

A key challenge in studying reward processing in humans is to go beyond subjective self-report measures and quantify different aspects of reward such as ...

Addenbrooke's Hospital

We used functional magnetic resonance imaging to explore brain responses to food images in overweight humans, examining independently the impact of a prescan meal ("satiety") and the anti-obesity drug sibutramine, a serotonin and noradrenaline reuptake inhibitor. We identified significantly different responses to these manipulations in amygdala, hypothalamus, and ventral striatum. Each region was specifically responsive to high-calorie compared to low-calorie food images. However, the ventral striatal response was attenuated by satiety (but unaffected by sibutramine), while the hypothalamic and amygdala responses were attenuated by drug but unaffected by satiety. Direct assessment of regional interactions confirmed the significance of this double dissociation. We explored the regional responses in greater detail by determining whether they were predictive of eating behavior and weight change. We observed that across the different regions, the individual-specific magnitude of drug- and satiety-induced modulation was associated with both variables: the sibutramine-induced modulation of the hypothalamic response was correlated with the drug's impact on both weight and subsequently measured ad libitum eating. The satiety-induced modulation of striatal response also correlated with subsequent ad libitum eating. These results suggest that hypothalamus and amygdala have roles in the control of food intake that are distinct from those of ventral striatum. Furthermore, they support a regionally specific effect on brain function through which sibutramine exerts its clinical effect.

Distinct modulatory effects of satiety and sibutramine on brain responses to food images in humans: a double dissociation across hypothalamus, amygdala, and ventral striatum.

Disturbances in the subjective experience of time have been observed both in schizophrenia and following acute administration of ketamine. However, effects of ketamine on more objective timing tasks have not yet been measured in humans, nor has it been established that timing effects are not merely secondary to a more general dysfunction in working memory (WM).

Ketamine perturbs perception of the flow of time in healthy volunteers.

Binge eating is associated with obesity and has been conceptualized as "food addiction." However, this view has received only inconsistent support in humans, and limited evidence relates key neurocircuitry to the disorder. Moreover, relatively few studies have used pharmacologic functional magnetic resonance imaging to probe the underlying basis of altered eating behaviors.

Article	Year
Distinct modulatory effects of satiety and sibutramine on brain responses to food images in humans: a double dissociation across hypothalamus, amygdala, and ventral striatum. The Journal of neuroscience : the official journal of the Society for Neuroscience\| PubMed ID: 20980590	2010
Ketamine perturbs perception of the flow of time in healthy volunteers. Psychopharmacology\| PubMed ID: 21603893	2011
Neural and behavioral effects of a novel mu opioid receptor antagonist in binge-eating obese people. Biological psychiatry\| PubMed ID: 23245760	2013

Victoria C. Cambridge

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