Roles of NMDA and dopamine in food-foraging decision-making strategies of rats in the social setting

BMC Neuroscience, Jan 2016

Background In highly complex social settings, an animal’s motivational drive to pursue an object depends not only on the intrinsic properties of the object, but also on whether the decision-making animal perceives an object as being the most desirable among others. Mimetic desire refers to a subject’s preference for objects already possessed by another subject. To date, there are no appropriate animal models for studying whether mimetic desire is at play in guiding the decision-making process. Furthermore, the neuropharmacological bases of decision-making processes are not well understood. In this study, we used an animal model (rat) to investigate a novel food-foraging paradigm for decision-making, with or without a mimetic desire paradigm. Results Faced with the choice of foraging in a competitive environment, rats preferred foraging for the desirable object, indicating the rats’ ability for decision-making. Notably, treatment with the non-competitive N-methyl-d-aspartate receptor antagonist MK-801, but not with the dopamine D1 or D2 receptor antagonists, SCH23390 and haloperidol, respectively, suppressed the food foraging preference when there was a competing resident rat in the cage. None of these three antagonists affected the food-foraging preference for palatable food. Moreover, MK-801 and SCH23390, but not haloperidol, were able to abolish the desirable environment effect on standard food-foraging activities in complex social settings. Conclusions These results highlight the concept that mimetic desire exerts a powerful influence on food-foraging decision-making in rats and, further, illustrate the various roles of the glutamatergic and dopaminergic systems in mediating these processes.

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Roles of NMDA and dopamine in food-foraging decision-making strategies of rats in the social setting

Li et al. BMC Neurosci Roles of NMDA and dopamine in food-foraging decision-making strategies of rats in the social setting Fang Li 0 WenY‑u Cao 0 Fu‑Lian Huang 0 WenJ‑ing Kang 0 Xiao‑Lin Zhong 0 Zhao‑Lan Hu 0 HongT‑ao Wang 0 Juan Zhang 0 JianY‑i Zhang 0 Ru‑Ping Dai 2 Xin‑Fu Zhou 1 Chang‑Qi Li 0 0 Department of Anatomy and Neurobiology, School of Basic Medical Science, Central South University , Tongzipo Road 172, Changsha 410013, Hunan , China 1 School of Phar‐ macy and Medical Sciences, Sansom Institute, University of South Australia , Adelaide, SA , Australia 2 Department of Anesthesia, the Second XiangYa Hospital, Central South University , Ren‐Min Road 86, Changsha, Hunan , China Background: In highly complex social settings, an animal's motivational drive to pursue an object depends not only on the intrinsic properties of the object, but also on whether the decision‑ making animal perceives an object as being the most desirable among others. Mimetic desire refers to a subject's preference for objects already possessed by another subject. To date, there are no appropriate animal models for studying whether mimetic desire is at play in guiding the decision‑ making process. Furthermore, the neuropharmacological bases of decision‑ making processes are not well understood. In this study, we used an animal model (rat) to investigate a novel food‑ foraging paradigm for decision‑ making, with or without a mimetic desire paradigm. Results: Faced with the choice of foraging in a competitive environment, rats preferred foraging for the desirable object, indicating the rats' ability for decision‑ making. Notably, treatment with the non‑ competitive N‑ methyl‑ d‑ aspartate receptor antagonist MK‑ 801, but not with the dopamine D1 or D2 receptor antagonists, SCH23390 and haloperidol, respectively, suppressed the food foraging preference when there was a competing resident rat in the cage. None of these three antagonists affected the food‑ foraging preference for palatable food. Moreover, MK‑ 801 and SCH23390, but not haloperidol, were able to abolish the desirable environment effect on standard food‑ foraging activities in complex social settings. Conclusions: These results highlight the concept that mimetic desire exerts a powerful influence on food‑ foraging decision‑ making in rats and, further, illustrate the various roles of the glutamatergic and dopaminergic systems in mediating these processes. Food‑ foraging behavior; Social decision‑ making; Mimetic desire; Rats Background Because rodents are highly social animals, many of their important social decisions, including choice of mate and food-foraging, are made within the social setting [ 1, 2 ]. Social decision-making, an enormously complex cognitive function, is typically made by cooperation with and conflict among conspecifics [ 3, 4 ]. In social psychology, the mimetic desire phenomenon, recognized as social contagion and a widespread strategy in nature, is one in which an object belonging to one person tends to become a goal for the observer. In humans, mimetic desire is able to effectively influence pursuit  of an object [ 5 ]. In addition to competitive food-snatching from other animals in the social setting, food-foraging decision-making is a process modulated by environmental factors and/or nutritional needs [ 6–9 ]. Due to the complexity of these processes, both the required interactive scenario, along with straightforward experimental manipulations, present challenges in the controlled laboratory setting. Our previous investigations successfully created an ideal foodforaging animal (rat) model capable of quantitatively demonstrating natural food-foraging behavior without either artificial interventions or training [10]. We found that food-foraging is associated not only with the choices animals make but also with higher cognitive functions [ 11, 12 ]. A growing body of studies in behavioral economics have used non-invasive neuroimaging techniques, such as functional magnetic resonance imaging (fMRI) and magnetoencephalography, and computational approaches to investigate the neural mechanisms behind sophisticated decision-making strategies [ 13–16 ]. A recent fMRI study reported that the human anterior cingulate cortex (ACC) is able to encode environmental signals as reflecting estimates of the richness and cost of the foraging environment [17]. Many psychiatric disorders involve deficits in decisionmaking, as well as dysregulated dopamine and/or dopamine receptor expressions [ 18, 19 ]. Additional studies have suggested that dopamine and/or dopamine receptors play vital roles in modulating the balance between effort and benefit, and goal-directed action selection, encoding the differences between actual and expected rewards [ 20, 21 ]. Dopamine receptors interact strongly with N-methyl-d-aspartate (NMDA) receptors, and the activities of each receptor mediates dissociably cost/ benefit decision-making processes by means of eff (...truncated)


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Fang Li, Wen-Yu Cao, Fu-Lian Huang, Wen-Jing Kang, Xiao-Lin Zhong, Zhao-Lan Hu, Hong-Tao Wang, Juan Zhang, Jian-Yi Zhang, Ru-Ping Dai, Xin-Fu Zhou, Chang-Qi Li. Roles of NMDA and dopamine in food-foraging decision-making strategies of rats in the social setting, BMC Neuroscience, 2016, pp. 3, 17, DOI: 10.1186/s12868-015-0233-8