Beierholm, U., Guitart-Masip, M., Economides, M., Chowdhury, R., Düzel, E., Dolan, R. J., & Dayan, P. (2013). Dopamine modulates reward-related vigor. Neuropsychopharmacology, 38, 1495-1503. doi:10.1038/npp.2013.48.