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How do humans make choices between different types of rewards? Economists have long argued on theoretical grounds that humans typically make these choices as if the values of the options they consider have been mapped to a single common scale for comparison. Neuroimaging studies in humans have recently begun to suggest the existence of a small group of(More)
The ability of human subjects to choose between disparate kinds of rewards suggests that the neural circuits for valuing different reward types must converge. Economic theory suggests that these convergence points represent the subjective values (SVs) of different reward types on a common scale for comparison. To examine these hypotheses and to map the(More)
Recent studies show that the nervous system contains many molecularly distinct cell types. Clonal cell marking experiments demonstrate that different cell types in some areas of the CNS are products of a multipotential stem cell. The factors controlling the differentiation of vertebrate CNS precursor cells would be more accessible to molecular analysis if(More)
The internal state of an organism affects its choices. Previous studies in various non-human animals have demonstrated a complex, and in some cases non-monotonic, interaction between internal state and risk preferences. Our aim was to examine the systematic effects of deprivation on human decision-making across various reward types. Using both a(More)
According to the United Nations, approximately 24.7 million people used am-phetamines, 16 million used cocaine, and 12 million used heroin in 2006/07 [Costa, 2008]. Full recovery from drug addiction by chemical treatment and/or social and psychological support is uncertain. The present investigation was undertaken to expand our understanding of the factors(More)
The HT4 cell line was derived from infection of a mouse neuroblastoma cell line with a retrovirus that encoded the temperature-sensitive (ts) mutant of SV40 large T antigen. At nonpermissive temperature, HT4 cells differentiated with neuronal morphology, expressed neuronal antigens, synthesized nerve growth factor (NGF) mRNA, and secreted biologically(More)
Personalized medicine is rapidly evolving with the objective of providing a patient with medications based on the "use of genetic susceptibility or pharmacogenetic testing to tailor an individual's preventive care or drug therapy" [1]. It is reasonable to foresee that this domain will incorporate sources of biological knowledge other than genetics including(More)
Drug addiction is a worldwide epidemic. To reduce its spread, understanding the nature of addiction is crucial and possible treatments have to be developed. Current models of drug addiction only explain why addiction is overwhelming and cannot be overcome. Instead we focus on the dynamic of addiction, which includes rehabilitation and relapse. The model(More)
The allostatic theory of drug abuse describes the brain's reward system alterations as substance misuse progresses. Neural adaptations arising from the reward system itself and from the antireward system provide the subject with functional stability, while affecting the person's mood. We propose a computational hypothesis describing how a virtual subject's(More)
Relapse is the chief problem of drug addiction where a successfully abstinent patient returns to seemingly extinct manners of drug consumption. While various parameters were identified as affecting relapse, the general dynamics of drug consumption is yet to be understood. We introduce a model that describes addiction focusing on a single state-value factor,(More)