PMID-21810782[0] Deep Brain Stimulation of Subthalamic Nuclei Affects Arm Response Inhibition In Parkinson’s Patients
- Inhibitory control is improved only when both DBS are active, that is, the reaction time to the stop signal is significantly shorter in the DBS-ON condition than in all the others (left, right, or neither).
- Inhibition is probably not lateralized.
- CF [1]
- The STN plays a critical role in the control of movements by integrating cortical inputs from several motor areas (Mink 1996, Romanelli et al 2005) (but how -- in what role?)
- Alteration of STN functioning leads to loss of the ability to control movements as in the case of Parkinson's disease (Obeso et al 2008).
- This control can be partially restored by DBS (Perlmutter and Mink 2006).
- I don't agree with this. Things are far more nuanced, and the STN likely has a different role.
- Theri metric is the SSRT:the stop signal reaction time.
- One study found that SSRT was longer when DBS was on.
- Two others bilateral DBS decreased length of the SSRT.
- This task creates conflict on all trials, as they are instructed to both move as fast as possible, but also avoid hitting the target on stop trials.
- In healthy subjects this leads to a delay strategy.
- SSRT is not measured, but rather estimated from a 'race condition' between Go and Stop cues.
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- They propose that DBS affects the procrastination strategy, and that this strategy was less often adopted by PD patients than normal controls.
- Or that STN / BG affects the ability to stop currently proceeding active movements.
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[0] Mirabella G, Iaconelli S, Romanelli P, Modugno N, Lena F, Manfredi M, Cantore G, Deep Brain Stimulation of Subthalamic Nuclei Affects Arm Response Inhibition In Parkinson's Patients.Cereb Cortex no Volume
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no Pages
(2011 Aug 1) |
[1] Frank MJ, Samanta J, Moustafa AA, Sherman SJ, Hold your horses: impulsivity, deep brain stimulation, and medication in parkinsonism.Science 318:5854, 1309-12 (2007 Nov 23) |
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