The opioid system consists of three receptors, mu, delta, and kappa, which are activated by
endogenous opioid peptides processed from three protein precursors, proopiomelanocortin …

The hypothesis that dopamine is important for reward has been proposed in a number of
forms, each of which has been challenged. Normally, rewarding stimuli such as food, water …

The theory is advanced that the common denominator of a wide range of addictive
substances is their ability to cause psychomotor activation. This view is related to the theory …

[Avena, NM, Rada, P., Hoebel BG, 2007. Evidence for sugar addiction: Behavioral and
neurochemical effects of intermittent, excessive sugar intake. Neuroscience and …

The publication of the psychomotor stimulant theory of addiction in 1987 and the finding that
addictive drugs increase dopamine concentrations in the rat mesolimbic system in 1988 …

primate research suggests that affiliation is a highly complex construct. studies of primate
affiliation demonstrate the need to distinguish between various affiliative behaviors, consider …

In this review we will critically assess the hypothesis that the reinforcing effect of virtually all
drugs of abuse is primarily dependent on activation of the mesolimbic dopamine system …

The natural incentives that shape behavior reach the central circuitry of motivation trans-
synaptically, via the five senses, whereas the laboratory rewards of intracranial stimulation …

Objective: The goal was to determine whether withdrawal from sugar can cause signs of
opioid dependence. Because palatable food stimulates neural systems that are implicated in …

Social play behavior is one of the earliest forms of non-mother-directed social behavior
appearing in ontogeny in mammalian species. During the last century, there has been a lot …