Andart

Built up those prefrontal muscles!

Changes in Cortical Dopamine D1 Receptor Binding Associated with Cognitive Training -- McNab et al. 323 (5915): 800 -- Science shows a cute result of training working memory: increased dopamine D1 receptor binding. This might explain how the improvement in working memory comes about. Since Torkel has earlier used the same training to treat kids with ADHD, a re-tuning of dopamine might make sense.

Wild speculation: I wonder if it also has effects on the reward system and hence personality? It could also change the setpoint of the inverted-U curve of dopamine response.