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Journal Article 2009; 30(5): 663-670 PubMed PMID: 20035259 Citation  Keywords:  Animals, Behavior, Animal:drug effects, Central Nervous System Stimulants:administration & dosage, Estradiol:pharmacology, Female, Humans, Infusions, Intravenous, Male, Methamphetamine:administration & dosage, Ovariectomy, Rats, Rats, Wistar, Reinforcemen.   

OBJECTIVE: The female animals were already recorded to respond differently to methamphetamine (MET) abuse than males. This gender dissimilarity may be caused by the influence of estral cycles and different susceptibility to behavioural sensitization.

METHODS: Influences of gender and pre-exposure to MET were studied in the rat model of MET intravenous self-administration (IVSA). The fixed ratio (FR) paradigm was employed in male rats (M) and estrogenized (F-ESTR) and non-estrogenized ovariectomized female rats (F-OVX) either pre-exposed or not-exposed to MET pretreatment.

RESULTS: In rats that were not pre-exposed to MET, F-ESTR self-administered more MET infusions than each of the other groups, but F-OVX self-administered less than each of the other groups; the same trend was apparent in the MET pretreated groups. MET pre-exposure decreased subsequent MET IVSA in all groups except F-OVX.

CONCLUSION: Thus, pre-exposure to MET and the loss of inherent estrogen in females notably decreased the intake of MET by rats, suggesting that abuse liability was reduced. Estrogen's effects on MET self-administration here correspond with accumulating evidence of stronger behavioural responses of females to drugs of abuse....

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Journal Article 2009; 30(2): 185-191 PubMed PMID: 19675524 Citation  Keywords:  Attention, Choice Behavior, Culture, Economics, Humans, Models, Neurological, Reinforcement (Psychology), Time Factors,.   

: According to theories of cultural neuroscience, Westerners and Easterners may have distinct styles of cognition (e.g., different allocation of attention). Previous research has shown that Westerners and Easterners tend to utilize analytical and holistic cognitive styles, respectively. On the other hand, little is known regarding the cultural differences in neuroeconomic behavior. For instance, economic decisions may be affected by cultural differences in neurocomputational processing underlying attention; however, this area of neuroeconomics has been largely understudied. In the present paper, we attempt to bridge this gap by considering the links between the theory of cultural neuroscience and neuroeconomic theory of the role of attention in intertemporal choice. We predict that (i) Westerners are more impulsive and inconsistent in intertemporal choice in comparison to Easterners, and (ii) Westerners more steeply discount delayed monetary losses than Easterners. We examine these predictions by utilizing a novel temporal discounting model based on Tsallis' statistics (i.e. a q-exponential model). Our preliminary analysis of temporal discounting of gains and losses by Americans and Japanese confirmed the predictions from the cultural neuroeconomic theory. Future study directions, employing computational modeling via neural networks, are outlined and discussed....

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Journal Article 2007; 28(5): 659-661 PubMed PMID: 17984946 Citation  Keywords:  Adult, Behavior, Addictive:psychology, Cerebral Cortex:physiology, Choice Behavior, Conflict (Psychology), Decision Making, Games, Experimental, Humans, Male, Reinforcement (Psychology), Smoking:psychology, Socioeconomic Factors,.   

OBJECTIVE: No study to date compared degrees of inequity aversion in economic decision-making in the ultimatum game between non-addictive and addictive reinforcers. The comparison is potentially important in neuroeconomics and reinforcement learning theory of addiction.

METHODS: We compared the degrees of inequity aversion in the ultimatum game between money and cigarettes in habitual smokers.

RESULTS: Smokers avoided inequity in the ultimatum game more dramatically for money than for cigarettes; i.e., there was a "domain effect" in decision-making in the ultimatum game.

CONCLUSIONS: Reward-processing neural activities in the brain for non-addictive and addictive reinforcers may be distinct and the insula activation due to cue-induced craving may conflict with unfair offer-induced insula activation. Future studies in neuroeconomics of addiction should employ game-theoretic decision tasks for elucidating reinforcement learning processes in dopaminergic neural circuits....

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