Depue & Collins [D&C] propose a well-conceived and nicely detailed theory of the involvement of dopaminergic connections in extraversion. Since these systems are hypothesized to be associated with reward sensitivity, other neural systems that are involved with reward sensitivity should be considered as well. In this commentary it is argued that there is now enough evidence for the involvement of the left and right frontal regions of the brain in approach and withdrawal behavior that it should also be considered in theories of personality such as D&C's. Integration of predominantly subcortical and cortical theories of personality/brain function may produce a more comprehensive picture of temperament and personality.