Saturday, March 21, 2015

Dopamine Promotes All-are-alike Behavior in Humans

Dopamine [4-(2-Aminoethyl)benzene-1,2-diol] is a hormone that  functions as a neurotransmitter-a chemical released by nerve cells to send signals to other nerve cells. Several important diseases of the nervous system are associated with dysfunctions of the dopamine system. Parkinson's disease, a degenerative condition causing tremor and motor impairment, has been related to the loss of dopamine-secreting neurons in the midbrain area called the substantia nigra.

Tolcapone [(3,4-dihydroxy-5-nitrophenyl)(4-methylphenyl)methanone] is a selective inhibitor of the enzyme catechol-O-methyl transferase (COMT). It is used in the treatment of Parkinson’s disease as an adjunct to levodopa/carbidopa medication.

Many articles in the literature point suggest that there is a link between dopamine and Egalitarian behavior. Egalitarianism is characterized by belief in the equality of all people, especially in political, economic, or social life. 

In a unique experiment step-up researchers using a combination of pharmacological tools and economic games, provide critical evidence for a causal involvement of dopamine in human egalitarian tendencies. Tolcapone and a placebo was provided to different set of volunteers, the results were then investigated to explain the relationship between dopaminergic mechanisms and two pro-social concerns at the core of a number of widely used economic games: (1) the extent to which individuals directly value the material payoffs of others, i.e., generosity, and (2) the extent to which they are averse to differences between their own payoffs and those of others, i.e., inequity.

Researchers found that dopaminergic augmentation via COMT inhibition increased egalitarian tendencies in participants. Further, using a computational modeling of choice behaviour, it is revealed that tolcapone exerted selective effects on inequity aversion, and not on other computational components.

The authors conclude as “These data shed light on the causal relationship between neurochemical systems and human prosocial behavior and have potential implications for understanding of the complex array of social impairments accompanying neuropsychiatric disorders involving dopaminergic dysregulation”.

Article citation: Kayer, A.; et. al. Dopamine Modulates Egalitarian Behavior in Humans. Current Biology Mar 2015. DOI: