Phase matters: A role for the subthalamic network during gait

Area of Science:

• Neuroscience
• Movement Disorders
• Biomedical Engineering

Background:

• The subthalamic nucleus's role in human locomotion remains unclear.
• Gait disturbances are a challenge in Parkinson's disease management, especially with subthalamic deep brain stimulation.
• Understanding subthalamic nucleus function is crucial for improving Parkinson's disease treatments.

Purpose of the Study:

• To investigate subthalamic nucleus activity and inter-hemispheric connectivity during walking in Parkinson's disease patients.
• To compare subthalamic nucleus function during rest, standing, and walking.
• To explore the relationship between subthalamic nucleus activity, gait, and dopamine levels.

Main Methods:

• Electrophysiological recordings in eight freely-moving Parkinson's disease patients with bilateral deep brain stimulation.
• Analysis of subthalamic power spectral densities and inter-hemispheric coherence, cross-correlation, and phase locking value.
• Comparison across resting state, upright standing, and steady forward walking conditions.

Main Results:

• A significant drop in phase locking value within the beta-frequency band (13-35Hz) was observed during walking compared to resting and standing.
• No significant changes in subthalamic power spectral densities were found during walking.
• Subthalamic nucleus activity modulation was not correlated with gait phases or striatal dopamine loss.

Conclusions:

• Subthalamic nucleus inter-hemispheric desynchronization in the beta-frequency band may support linear walking by enabling separate processing of each body side.
• Brain signals for feedback-controlled stimulation during gait might originate from network activity.
• This finding offers insights into the neural mechanisms of gait control and potential therapeutic targets in Parkinson's disease.