Stimulation of Subthalamic Nuclei Restores a Near Normal Planning Strategy in Parkinson’s Patients

Abstract

A fundamental function of the motor system is to gather key information from the environment in order to implement behavioral strategies appropriate to the context. Although several lines of evidence indicate that Parkinson’s disease affects the ability to modify behavior according to task requirements, it is currently unknown whether deep brain stimulation (DBS) of the subthalamic nucleus (STN) affects context-related planning. To explore this issue, we asked 12 Parkinson’s patients with bilateral STN DBS and 13 healthy subjects to execute similar arm reaching movements in two different paradigms: go-only and countermanding tasks. In the former task patients had to perform speeded reaching movements to a peripheral target. In contrast, in the countermanding task participants had to perform the same reaches unless an infrequent and unpredictable stop-signal was shown during the reaction time (RT) indicating that they should withhold the ongoing action. We compared the performance of Parkinson’s patients in different DBS conditions. We found that patients with both DBS-ON behaved similarly to healthy subjects, in that RTs of no-stop trial increased while movement times (MTs) decreased with respect to those of go-only-trials. However, when both DBS were off, both RTs and MTs were longer in no-stop trials than in go-only trials. These findings indicate that bilateral DBS of STN can partially restore the appropriate motor strategy according to the given cognitive contexts.

Network effects of deep brain stimulation

“…These findings suggest that disrupting the STN locally may affect functionally connected cortical regions via differential effects on two different circuits converging in the STN (Wylie et al 2010). Likewise, a recent study of the effects of STN stimulation on go-only and countermanding tasks also indicated that both inhibitory control and the selection of the most appropriate motor strategy for a given context may be regulated by two different circuits that both include the STN (Mirabella et al 2013).…”

Compensatory stepping in Parkinson's disease is still a problem after deep brain stimulation randomized to STN or GPi

“…Ray et al (2009) show that STN DBS improves inhibitory control in patients with initially worse SST compared with control subjects; however, when SST was initially in the range of control subjects, inhibitory responses are impaired by STN DBS (Ray et al 2009). Furthermore, while proactive inhibition is reported to be enhanced by STN DBS (Mirabella et al 2013;Obeso et al 2013), reactive inhibition is worsened (Obeso et al 2013). Together, the literature suggests that the STN affects motor inhibition through parallel pathways, which may have positive or negative effects depending on the context and the nature of the motor task.…”

Developmental Coordination Disorder Affects the Processing of Action-Related Verbs

“…Our analyses were motivated by the fact that on the one hand reaching movements are not ballistic and thus, in principle the MTs can be modulated according to the context at play (e.g., Mirabella et al, 2008, 2013). On the other hand, Desai et al (2015) showed that implicit, but not explicit semantic action verb processing are related to the MTs.…”