Does cognitive training enhance dopamine release?

Question

Joe Hardy reports on a study by Backman et al (2011) in Science, where from the authors report:

Updating of working memory has been associated with striato-frontal brain regions and phasic dopaminergic neurotransmission. We assessed raclopride binding to striatal dopamine (DA) D2 receptors during a letter-updating task and a control condition before and after 5 weeks of updating training. Results showed that updating affected DA activity before training and that training further increased striatal DA release during updating. These findings highlight the pivotal role of transient neural processes associated with D2 receptor activity in working memory.

Joe Hardy goes on to claim:

This result shows that cognitive training with exercises similar to those on Lumosity can change the way the brain works at a fundamental chemical level. Indeed, we’ve known for several years that the right kind of cognitive training can enhance brain functions like working memory.

Question

• Is it true that cognitive training enhances dopamine release ?
• Are there any studies that disprove this ?

References

• Backman, L., Nyberg, L., Soveri, A., Johansson, J., Andersson, M., Dahlin, E., Neely, A.S., Virta, J., Laine, M. & Rinne, J.O. (2011). Effects of working-memory training on striatal dopamine release. Science, 333, 718.

Answer 1

The paper claims that training on updating (based on the influential view of executive function proposed by Miyake et al., 2000) tasks, which require maintaining and manipulating information in WM in response to new input or feedback, transfers to other memory tasks such as letter-memory and n-back, and that this transfer is associated with changes in phasic dopamine activity.

Hardy is therefore stretching the study conclusions quite far here. As Tyler Langan notes in his comment to the question, the effect of a neurotransmitter is enormously dependent on a number of factors beyond the type of transmitter, such as exactly where it is released, and for how long it is released, among others. In some sufficiently broad sense, it is probably true that "cognitive training leads to enhanced dopamine release," but I don't necessarily think that is meaningful in any explanatory sense.

When interpreting fMRI studies, it is always important to consider very, very carefully the exact relationship between the evidence and the claim, especially when venturing beyond the careful boundaries set down by the original authors. Consider, for instance, the carefully bounded conclusion reached by the original authors:

Our data are consistent with findings of displacement of ligand binding to D2 receptors during cognitive processing (5, 8) and indicate a link between previously observed increases of BOLD activity after WM training (1) and DA release.

Contrast with Hardy's more free-style take on the matter:

This result shows that cognitive training with exercises similar to those on Lumosity can change the way the brain works at a fundamental chemical level.

That's not technically incorrect, at least not as such, but it is disingenuous. In the particular sense his claim is "not incorrect," it is also "not incorrect" to say that virtually any other activity performed over a long enough time-span (e.g. five weeks) "can change the way the brain works at a fundamental chemical level." Changing at the chemical level is a part of how the brain works, and what the study by Backman et al. illustrates is a specific way it changes under certain conditions.

References

Miyake, A., Friedman, N. P., Emerson, M. J., Witzki, A. H., Howerter, A., & Wager, T. D. (2000). The unity and diversity of executive functions and their contributions to complex “Frontal Lobe” tasks: a latent variable analysis. Cognitive Psychology, 41(1), 49–100. doi:10.1006/cogp.1999.0734

(link to pdf)