STN stimulation alters pallidal-frontal coupling during response selection under competition

Area of Science:

• Neuroscience
• Neurology
• Neurosurgery

Background:

• Parkinson's disease (PD) affects motor control and cognitive functions.
• Subthalamic nucleus (STN) deep brain stimulation (DBS) is a common PD treatment.
• Cognitive tasks like random number generation (RNG) assess executive functions.

Purpose of the Study:

• To investigate the impact of bilateral STN DBS on brain activation during RNG.
• To examine how STN DBS affects cognitive control and response selection.
• To understand the neural mechanisms underlying STN DBS effects on executive function.

Main Methods:

• H(2)(15)O positron emission tomography (PET) to measure regional cerebral blood flow (rCBF).
• Six Parkinson's disease patients undergoing bilateral STN DBS.
• Comparison of paced RNG (1 Hz) with a control counting task, with DBS on and off, off medication.

Main Results:

• STN DBS worsened RNG performance, reducing randomness and increasing habitual counting.
• STN DBS decreased rCBF in prefrontal and cingulate cortices.
• STN DBS increased rCBF in the right internal globus pallidus (GPi) and altered pallidal connectivity.

Conclusions:

• STN DBS activates STN output neurons projecting to the GPi.
• STN DBS leads to increased inhibition of a prefrontal-cingulate network.
• This study provides direct evidence of STN DBS altering cortico-pallidal coupling during cognitive tasks.