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Insulin, Central Dopamine D2 Receptors, and Monetary Reward Discounting in Obesity.

Eisenstein SA, Gredysa DM, Antenor-Dorsey JA, Green L, Arbeláez AM, Koller JM, Black KJ, Perlmutter JS, Moerlein SM, Hershey T - PLoS ONE (2015)

Bottom Line: Choice of larger, but delayed or less certain, monetary rewards relative to immediate, certain smaller monetary rewards was measured using delayed and probabilistic reward discounting tasks.Higher percent body fat in non-obese women related to preference for a smaller, certain reward over a larger, less likely one (greater probabilistic discounting).These results raise interesting questions about whether and how striatal D2 receptor binding and metabolic factors, including β-cell function, interact to affect reward discounting in humans.

View Article: PubMed Central - PubMed

Affiliation: Psychiatry Department, Washington University in St. Louis, St. Louis, MO, United States of America; Radiology Department, Washington University in St. Louis, St. Louis, MO, United States of America.

ABSTRACT
Animal research finds that insulin regulates dopamine signaling and reward behavior, but similar research in humans is lacking. We investigated whether individual differences in body mass index, percent body fat, pancreatic β-cell function, and dopamine D2 receptor binding were related to reward discounting in obese and non-obese adult men and women. Obese (n = 27; body mass index>30) and non-obese (n = 20; body mass index<30) adults were assessed for percent body fat with dual-energy X-ray absorptiometry and for β-cell function using disposition index. Choice of larger, but delayed or less certain, monetary rewards relative to immediate, certain smaller monetary rewards was measured using delayed and probabilistic reward discounting tasks. Positron emission tomography using a non-displaceable D2-specific radioligand, [11C](N-methyl)benperidol quantified striatal D2 receptor binding. Groups differed in body mass index, percent body fat, and disposition index, but not in striatal D2 receptor specific binding or reward discounting. Higher percent body fat in non-obese women related to preference for a smaller, certain reward over a larger, less likely one (greater probabilistic discounting). Lower β-cell function in the total sample and lower insulin sensitivity in obese related to stronger preference for an immediate and smaller monetary reward over delayed receipt of a larger one (greater delay discounting). In obese adults, higher striatal D2 receptor binding related to greater delay discounting. Interestingly, striatal D2 receptor binding was not significantly related to body mass index, percent body fat, or β-cell function in either group. Our findings indicate that individual differences in percent body fat, β-cell function, and striatal D2 receptor binding may each contribute to altered reward discounting behavior in non-obese and obese individuals. These results raise interesting questions about whether and how striatal D2 receptor binding and metabolic factors, including β-cell function, interact to affect reward discounting in humans.

No MeSH data available.


Related in: MedlinePlus

Insulin Function Relates to Delayed Reward Discounting in Total Sample and Obese Group.(A) β-cell function across the total sample and (B), insulin sensitivity in obese participants related to greater preference for a smaller but immediate monetary reward relative to one that was larger but delayed. Data points are standardized residuals of variables after controlling for age, gender, education, and ethnicity (and group in (A)). Clear data points, non-obese; filled data points, obese; DRDAuC, area under the curve for delayed reward discounting.
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pone.0133621.g002: Insulin Function Relates to Delayed Reward Discounting in Total Sample and Obese Group.(A) β-cell function across the total sample and (B), insulin sensitivity in obese participants related to greater preference for a smaller but immediate monetary reward relative to one that was larger but delayed. Data points are standardized residuals of variables after controlling for age, gender, education, and ethnicity (and group in (A)). Clear data points, non-obese; filled data points, obese; DRDAuC, area under the curve for delayed reward discounting.

Mentions: DI significantly related to DRDAuC within the total sample (Fig 2A, Table 2and S1 Table), such that individuals with higher β-cell function discounted delayed rewards at a lower rate than those with lower β-cell function. The significance level of this relationship in obese individuals was p = 0.05 but did not survive multiple comparison correction. In non-obese individuals, DI and DRDAuC were not significantly related (Table 2and S1 Table).


Insulin, Central Dopamine D2 Receptors, and Monetary Reward Discounting in Obesity.

Eisenstein SA, Gredysa DM, Antenor-Dorsey JA, Green L, Arbeláez AM, Koller JM, Black KJ, Perlmutter JS, Moerlein SM, Hershey T - PLoS ONE (2015)

Insulin Function Relates to Delayed Reward Discounting in Total Sample and Obese Group.(A) β-cell function across the total sample and (B), insulin sensitivity in obese participants related to greater preference for a smaller but immediate monetary reward relative to one that was larger but delayed. Data points are standardized residuals of variables after controlling for age, gender, education, and ethnicity (and group in (A)). Clear data points, non-obese; filled data points, obese; DRDAuC, area under the curve for delayed reward discounting.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4507849&req=5

pone.0133621.g002: Insulin Function Relates to Delayed Reward Discounting in Total Sample and Obese Group.(A) β-cell function across the total sample and (B), insulin sensitivity in obese participants related to greater preference for a smaller but immediate monetary reward relative to one that was larger but delayed. Data points are standardized residuals of variables after controlling for age, gender, education, and ethnicity (and group in (A)). Clear data points, non-obese; filled data points, obese; DRDAuC, area under the curve for delayed reward discounting.
Mentions: DI significantly related to DRDAuC within the total sample (Fig 2A, Table 2and S1 Table), such that individuals with higher β-cell function discounted delayed rewards at a lower rate than those with lower β-cell function. The significance level of this relationship in obese individuals was p = 0.05 but did not survive multiple comparison correction. In non-obese individuals, DI and DRDAuC were not significantly related (Table 2and S1 Table).

Bottom Line: Choice of larger, but delayed or less certain, monetary rewards relative to immediate, certain smaller monetary rewards was measured using delayed and probabilistic reward discounting tasks.Higher percent body fat in non-obese women related to preference for a smaller, certain reward over a larger, less likely one (greater probabilistic discounting).These results raise interesting questions about whether and how striatal D2 receptor binding and metabolic factors, including β-cell function, interact to affect reward discounting in humans.

View Article: PubMed Central - PubMed

Affiliation: Psychiatry Department, Washington University in St. Louis, St. Louis, MO, United States of America; Radiology Department, Washington University in St. Louis, St. Louis, MO, United States of America.

ABSTRACT
Animal research finds that insulin regulates dopamine signaling and reward behavior, but similar research in humans is lacking. We investigated whether individual differences in body mass index, percent body fat, pancreatic β-cell function, and dopamine D2 receptor binding were related to reward discounting in obese and non-obese adult men and women. Obese (n = 27; body mass index>30) and non-obese (n = 20; body mass index<30) adults were assessed for percent body fat with dual-energy X-ray absorptiometry and for β-cell function using disposition index. Choice of larger, but delayed or less certain, monetary rewards relative to immediate, certain smaller monetary rewards was measured using delayed and probabilistic reward discounting tasks. Positron emission tomography using a non-displaceable D2-specific radioligand, [11C](N-methyl)benperidol quantified striatal D2 receptor binding. Groups differed in body mass index, percent body fat, and disposition index, but not in striatal D2 receptor specific binding or reward discounting. Higher percent body fat in non-obese women related to preference for a smaller, certain reward over a larger, less likely one (greater probabilistic discounting). Lower β-cell function in the total sample and lower insulin sensitivity in obese related to stronger preference for an immediate and smaller monetary reward over delayed receipt of a larger one (greater delay discounting). In obese adults, higher striatal D2 receptor binding related to greater delay discounting. Interestingly, striatal D2 receptor binding was not significantly related to body mass index, percent body fat, or β-cell function in either group. Our findings indicate that individual differences in percent body fat, β-cell function, and striatal D2 receptor binding may each contribute to altered reward discounting behavior in non-obese and obese individuals. These results raise interesting questions about whether and how striatal D2 receptor binding and metabolic factors, including β-cell function, interact to affect reward discounting in humans.

No MeSH data available.


Related in: MedlinePlus