correcting the relationship between tonic and burst firing modes in dopamine neurons may help normalise stimulus-reinforcement gradients and contingent behaviour in attention-deficit/hyperactivity disorder (adhd) children. but appropriate evaluations of stimuli for developing adaptive plans and controlling impulsivity will not occur without moderating the gain-like functions of serotonin. the “dynamic theory” correctly highlights the need to account for variability in adhd. the dysmaturation of pre-executive information processing is proposed as an explanation.

at the core of the article by sagvolden and colleagues there is a set of data that throws light on an aspect of the adhd phenomenon. but one asks if the authors are a measure too brave to generalise so broadly from the unusually steep reinforcement gradients reported for the human condition and an animal model to the syndrome as a whole.