Chowdhury, R., Guitart-Masip, M., Lambert, C., Dolan, R. J., & Düzel, E. (2013).
Structural integrity of the substantia nigra and subthalamic nucleus predicts flexibility of instrumental learning in older-age
individuals. Neurobiology of Aging, 34, 2261-2270. doi:10.1016/j.neurobiolaging.2013.03.030.