Objective: To study the subthalamic nucleus (STN) and globus pallidus internus (GPi) local filed potential (LFP) activities in the response inhibition during masked prime tasks in parkinsonian and dystonia patients, respectively.

Background: It is suggested that the STN plays a key role in modulating response during conflict motor tasks in the basal ganglia circuit. It has been hypothesized that STN and its connections to cortical and other basal ganglia nuclei regulate the inhibition during conflict condition.

Methods: We recorded LFPs from deep brain stimulation (DBS) electrodes implanted bilaterally in the STN (n=8) and GPi (n=9) of human subjects with Parkinson’s disease and dystonia, respectively, while they performed a subliminally primed task. In the subliminally primed task, clearly observable right- or left-pointing target arrows are preceded by briefly presented and subsequently masked prime arrows. Subjects respond rapidly with a right or left key-press to each target. Trials were either compatible (prime and target pointing in the same direction) or incompatible (prime and target pointing in opposite directions).

Results: The congruent trials were executed with the shorter reaction times than incongruent trials in both patient groups. However, reaction time for PD subjects was significantly higher than dystonia and normal subjects. Beta power in the STN and GPi was decreased during the response. In congruent trails, amplitude of beta band was more reduced compared to incongruent trials during the response in the STN and GPi. However, in incongruent trials, beta activity briefly increased not only in the STN but also in the GPi prior to the response.

Conclusions: Current study concludes that modulation of beta band power in the STN and GPi is critical in the processing of action selection and response during the presence of conflict task. We suggest that both the STN and GPi are involved in the mechanism for response inhibition.

References: Brittain, John-Stuart, et al. “A role for the subthalamic nucleus in response inhibition during conflict.” The Journal of Neuroscience 32.39 (2012): 13396-13401.

Zavala, Baltazar, et al. “Subthalamic nucleus local field potential activity during the Eriksen flanker task reveals a novel role for theta phase during conflict monitoring.” The Journal of Neuroscience 33.37 (2013): 14758-14766.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/role-of-the-subthalamic-nucleus-and-globus-pallidus-internus-in-response-inhibition-during-masked-prime-tasks-in-human/