In the working memory task, the performance of unmedicated adults with ADHD suggests that they were not correctly updating memory with context information; medication changed this pattern, such that they began to look more like controls (actually showing more AY errors and less AX & BX errors, for those who are familiar with the task.)
Frank et al. conclude that the behavioral results broadly support computational models of dopamine, in which higher DA levels are important for both learning positive reinforcement and for correctly updating working memory. Similarly, high levels of noradrenaline release relate to errate behavior both in computational models and adults with ADHD, a disorder associated with NA abnormality.
Finally, Frank et al. also suggest that the infamous response inhibition deficits of ADHD may actually result from cerebellar malfunction (and associated impairments in precise timing of motor coordination), from exacerbated RT variability (resulting from NA abnormality), or from both cerebellar and NA dysfunction, rather than from DA specifically (although they do not rule out that possibility).