Damage to dorsolateral prefrontal cortex affects tradeoffs between honesty and self-interest
Lusha Zhu, Adrianna C Jenkins, Eric Set, Donatella Scabini, Robert T Knight, Pearl H Chiu, Brooks King-Casas, and Ming Hsu
Substantial correlational evidence suggests that prefrontal regions are critical to honest and dishonest behavior, but causal evidence specifying the nature of this involvement remains absent. We found that lesions of the human dorsolateral prefrontal cortex (DLPFC) decreased the effect of honesty concerns on behavior in economic games that pit honesty motives against self-interest, but did not affect decisions when honesty concerns were absent. These results point to a causal role for DLPFC in honest behavior.
Congratulations Eric! [PNAS Link]
Set and colleagues present an impressive study combining sophisticated modeling of strategic behavior and a sophisticated genetic modeling approach.
Dissociable contribution of prefrontal and striatal dopaminergic genes to learning in economic games
Eric Set, Ignacio Saez, Lusha Zhu, Daniel E. Houser, Noah Myung, Songfa Zhong, Richard P. Ebsteing, Soo Hong Chew, and Ming Hsu
Game theory describes strategic interactions where success of players’ actions depends on those of coplayers. In humans, substantial progress has been made at the neural level in characteriz ing the dopaminergic and frontostriatal mechanisms mediating such behavior. Here we combined computational modeling of strategic learning with a pathway approach to characterize association of strategic behavior with variations in the dopamine pathway. Specifically, using gene-set analysis, we systematically examined contribution of different dopamine genes to variation in a multistrategy competitive game captured by (i) the degree players anticipate and respond to actions of others (belief learning) and (ii) the speed with which such adaptations take place (learning rate). We found that variation in genes that primarily regulate prefrontal dopamine clearance—catechol-O-methyl transferase (COMT) and two isoforms of monoamine oxidase—modulated degree of belief learning across individuals. In contrast, we did not find significant association for other genes in the dopamine pathway. Furthermore, variation in genes that primarily regulate striatal dopamine function—dopamine transporter and D2 receptors—was significantly associated with the learning rate. We found that this was also the case with COMT, but not for other dopaminergic genes. Together, these findings highlight dissociable roles of frontostriatal systems in strategic learning and support the notion that genetic variation, organized along specific pathways, forms an important source of variation in complex phenotypes such as strategic behavior.