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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

Non-obese and Obese Individuals Show Similar Reward Discounting Tendencies.(A) The subjective value of a monetary reward ($500) decreased as time to its receipt increased (main effect of time: F4,120 = 54.10, p < .001) in a similar manner in non-obese and obese individuals (no main effect of group: F1,30 = .12, p = 0.73 or group x time interaction (F4,120 = .36, p = 0.84). (B) The subjective value of a monetary reward ($500) decreased as the odds against its receipt increased (main effect of time: F4,120 = 88.66, p<0.001) in a similar fashion in non-obese and obese groups (no main effect of group: F1,30 = .12, p = 0.73 or group x time interaction (F4,120 = .67, p = 0.62).
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pone.0133621.g001: Non-obese and Obese Individuals Show Similar Reward Discounting Tendencies.(A) The subjective value of a monetary reward ($500) decreased as time to its receipt increased (main effect of time: F4,120 = 54.10, p < .001) in a similar manner in non-obese and obese individuals (no main effect of group: F1,30 = .12, p = 0.73 or group x time interaction (F4,120 = .36, p = 0.84). (B) The subjective value of a monetary reward ($500) decreased as the odds against its receipt increased (main effect of time: F4,120 = 88.66, p<0.001) in a similar fashion in non-obese and obese groups (no main effect of group: F1,30 = .12, p = 0.73 or group x time interaction (F4,120 = .67, p = 0.62).

Mentions: Descriptive statistics for demographics and all study variables are summarized in Table 1. Non-obese and obese individuals differed significantly in BMI and PBF but not years of education or age. The non-obese and obese groups did not differ in gender distribution, but ethnicity distribution was different at a marginally significant level. β-cell function (DI) and insulin sensitivity (Matsuda ISI) were lower, and insulin secretion was higher, in obese relative to non-obese participants. Consistent with an overlapping sample in a previous publication from our lab [32], obese and non-obese groups did not differ significantly in striatal D2R BPND. Reward discounting behavior did not differ between the non-obese and obese groups on either delay discounting (DRDAuC) or probabilistic discounting (PRDAuC (Fig 1). DRDAuC and PRDAuC values were positively correlated across the total sample (r45 = .43, p<0.01), as well as within the non-obese (r19 = .51, p = 0.03) and obese (r26 = .39, p = 0.05) groups, such that greater preference for smaller and immediate monetary reward was associated with greater preference for smaller and certain ones.


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)

Non-obese and Obese Individuals Show Similar Reward Discounting Tendencies.(A) The subjective value of a monetary reward ($500) decreased as time to its receipt increased (main effect of time: F4,120 = 54.10, p < .001) in a similar manner in non-obese and obese individuals (no main effect of group: F1,30 = .12, p = 0.73 or group x time interaction (F4,120 = .36, p = 0.84). (B) The subjective value of a monetary reward ($500) decreased as the odds against its receipt increased (main effect of time: F4,120 = 88.66, p<0.001) in a similar fashion in non-obese and obese groups (no main effect of group: F1,30 = .12, p = 0.73 or group x time interaction (F4,120 = .67, p = 0.62).
© Copyright Policy
Related In: Results  -  Collection

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

pone.0133621.g001: Non-obese and Obese Individuals Show Similar Reward Discounting Tendencies.(A) The subjective value of a monetary reward ($500) decreased as time to its receipt increased (main effect of time: F4,120 = 54.10, p < .001) in a similar manner in non-obese and obese individuals (no main effect of group: F1,30 = .12, p = 0.73 or group x time interaction (F4,120 = .36, p = 0.84). (B) The subjective value of a monetary reward ($500) decreased as the odds against its receipt increased (main effect of time: F4,120 = 88.66, p<0.001) in a similar fashion in non-obese and obese groups (no main effect of group: F1,30 = .12, p = 0.73 or group x time interaction (F4,120 = .67, p = 0.62).
Mentions: Descriptive statistics for demographics and all study variables are summarized in Table 1. Non-obese and obese individuals differed significantly in BMI and PBF but not years of education or age. The non-obese and obese groups did not differ in gender distribution, but ethnicity distribution was different at a marginally significant level. β-cell function (DI) and insulin sensitivity (Matsuda ISI) were lower, and insulin secretion was higher, in obese relative to non-obese participants. Consistent with an overlapping sample in a previous publication from our lab [32], obese and non-obese groups did not differ significantly in striatal D2R BPND. Reward discounting behavior did not differ between the non-obese and obese groups on either delay discounting (DRDAuC) or probabilistic discounting (PRDAuC (Fig 1). DRDAuC and PRDAuC values were positively correlated across the total sample (r45 = .43, p<0.01), as well as within the non-obese (r19 = .51, p = 0.03) and obese (r26 = .39, p = 0.05) groups, such that greater preference for smaller and immediate monetary reward was associated with greater preference for smaller and certain ones.

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