Modifying the cortical processing for motor preparation by repetitive transcranial magnetic stimulation

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Motor Control

Background:

• Motor preparation is crucial for rapid, accurate movements.
• Understanding the neural mechanisms of motor preparation aids in treating motor disorders.

Purpose of the Study:

• To investigate the impact of repetitive transcranial magnetic stimulation (rTMS) on the central processing of motor preparation.
• To identify specific cortical areas involved in different aspects of motor preparation.

Main Methods:

• Subjects performed a precued-choice reaction time (RT) task with varying levels of advance information.
• 1-Hz rTMS was applied over different cortical areas before task performance.
• Reaction times and error rates were measured before and after rTMS intervention.

Main Results:

• rTMS significantly delayed RT within 10 minutes and between 20-90 minutes post-stimulation.
• The delay was more pronounced for left-hand responses.
• rTMS over premotor and motor cortices delayed RT irrespective of advance information.
• rTMS over supplementary motor area and anterior parietal cortex affected RT based on information availability.

Conclusions:

• rTMS temporarily impairs motor preparation, particularly affecting processes near motor output formation.
• Different cortical areas play distinct roles in integrating information for motor preparation.
• The primary motor cortex, especially on the left, may be critical for executing motor commands based on processed information.