title: The subthalamic nucleus is involved in successful inhibition in the stop-signal task: a local field potential study in Parkinson's disease.
abstract: Normal actions and behaviors often require inhibition of unwanted and inadequate movements. Motor inhibition has been studied using the stop signal task, in which participants are instructed to respond to a go signal. Sporadically, a stop signal is also delivered after a short interval following the go signal, prompting participants to inhibit their already started response to the go signal. Functional MRI studies using this paradigm have implicated the activation of the subthalamic nucleus in motor inhibition. We directly recorded subthalamic nucleus activity from bilaterally implanted deep brain stimulation electrodes in a group of 10 patients with Parkinson's disease, during performance of the stop signal task. Response inhibition was associated with specific changes in subthalamic activity in three different frequency bands. Response preparation was associated with a decrease in power and cortico-subthalamic coherence in the beta band (12-30 Hz), which was smaller and shorter when the response was successfully inhibited. In the theta band, we observed an increase in frontal cortico-subthalamic coherence related to the presence of the stop signal, which was highest when response inhibition was unsuccessful. Finally, a specific differential pattern of gamma activity was observed in the "on" motor state. Performance of the response was associated with a significant increase in power and cortico-subthalamic coherence, while successful inhibition of the response was associated with a bilateral decrease in subthalamic power and cortico-subthalamic coherence. Importantly, this inhibition-related decrease in gamma activity was absent in the four patients with dopamine-agonist related impulse-control disorders. Our results provide direct support for the involvement of the subthalamic nucleus in response inhibition and suggest that this function may be mediated by a specific reduction in gamma oscillations in the cortico-subthalamic connection.
authors.affiliation: Neurosciences Area, CIMA, University of Navarra, Pamplona, Spain.
authors.forename: Manuel
authors.initials: M
authors.lastname: Alegre
authors.forename: Jon
authors.initials: J
authors.lastname: Lopez-Azcarate
authors.forename: Ignacio
authors.initials: I
authors.lastname: Obeso
authors.forename: Leonora
authors.initials: L
authors.lastname: Wilkinson
authors.forename: Maria C
authors.initials: MC
authors.lastname: Rodriguez-Oroz
authors.forename: Miguel
authors.initials: M
authors.lastname: Valencia
authors.forename: David
authors.initials: D
authors.lastname: Garcia-Garcia
authors.forename: Jorge
authors.initials: J
authors.lastname: Guridi
authors.forename: Julio
authors.initials: J
authors.lastname: Artieda
authors.forename: Marjan
authors.initials: M
authors.lastname: Jahanshahi
authors.forename: Jose A
authors.initials: JA
authors.lastname: Obeso
mesh_terms: D000368:Aged; D000978:Antiparkinson Agents / Q000627:therapeutic use; D001611:Beta Rhythm / Q000502:physiology; D003627:Data Interpretation, Statistical; D046690:Deep Brain Stimulation; D004558:Electric Stimulation; D004567:Electrodes, Implanted; D004569:Electroencephalography; D055724:Electrophysiological Phenomena; D005071:Evoked Potentials / Q000502:physiology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000502:physiology; D009434:Neural Pathways / Q000502:physiology; D010300:Parkinson Disease / Q000503:physiopathology*; D011930:Reaction Time / Q000502:physiology; D012815:Signal Processing, Computer-Assisted; D020531:Subthalamic Nucleus / Q000502:physiology*; D013826:Theta Rhythm / Q000502:physiology
chemical_list: D000978:Antiparkinson Agents