Hold Your Horses: Impulsivity, Deep Brain Stimulation, and Medication in Parkinsonism

The use of Deep brain stimulation (DBS) of the subthalamic nucleus on the Parkinson's has diseasemarkedly improves the motor symptoms of Parkinson's disease, but causes cognitive side effects such as impulsivity. This article shows that DBS selectively interferes with the normal ability to slow down when faced with decision conflict. Under high-conflict situation, what a normal does is usually slow down and think twice and feel hard to make the final decision. However, while on DBS, PD's patients actually sped up their decisions under high-conflict conditions. This form of impulsivity was not affected by dopaminergic medication status. Instead, medication impaired patients' ability to learn from negative decision outcomes.
These findings implicate independent mechanisms leading to impulsivity in treated Parkinson's patients and were predicted by a single neurocomputational model of the basal ganglia. It tells the future research on Deep Brain Stimulation to take the cognitive conflict into account.

The article can be found at: http://www.sciencemag.org.ezproxy.tamu.edu:2048/cgi/content/full/318/5854/1309