Normalizing motor-related brain activity: subthalamic nucleus stimulation in Parkinson disease

Area of Science:

• Neuroscience
• Neurology
• Medical Imaging

Background:

• Parkinson disease (PD) is characterized by motor deficits due to basal ganglia dysfunction.
• Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is an effective treatment for PD.
• Altered brain activation patterns are observed in PD patients during motor tasks.

Purpose of the Study:

• To investigate the effects of therapeutic unilateral STN-DBS on brain activation patterns in PD patients.
• To determine if effective STN-DBS normalizes brain activity during movement execution and control.
• To identify specific brain regions affected by STN-DBS in PD.

Main Methods:

• Positron Emission Tomography (PET) imaging was used in six PD patients off medication.
• Patients performed a visually guided tracking task under effective and ineffective STN-DBS conditions.
• Data were compared to 13 age-matched controls; conjunction analysis identified normalized activation sites.

Main Results:

• Effective STN-DBS increased activation in the supplementary motor area (SMA), parietal cortex, and cerebellum during movement execution.
• Effective STN-DBS reduced SMA overactivity at rest and normalized motor control-related activity in motor cortex, SMA, and basal ganglia.
• Therapeutic stimulation reduced compensatory overactivity in prefrontal, temporal, and basal ganglia circuits compared to healthy subjects.

Conclusions:

• Effective STN-DBS induces task-specific modifications in motor area recruitment in PD.
• STN-DBS leads to widespread reductions in compensatory cortical activity.
• This study demonstrates STN-DBS normalizes brain activation patterns in Parkinson disease.