Theta-burst stimulation over primary motor cortex degrades early motor learning

Area of Science:

• Neuroscience
• Motor Control
• Cognitive Science

Background:

• Primary motor cortex (M1) plays a crucial role in motor learning.
• Theta-burst stimulation (TBS) is used to alter M1 excitability.
• The impact of inhibitory TBS on early motor learning requires further investigation.

Purpose of the Study:

• To investigate if continuous inhibitory TBS (cTBS) modulates early motor learning of a simple finger movement in healthy humans.
• To determine the effects of cTBS on motor performance, retention, and consolidation.

Main Methods:

• Healthy subjects received real or sham cTBS over the left M1 during finger movement practice.
• Motor evoked potentials were recorded to assess M1 excitability.
• Kinematic variables (amplitude, peak velocity, acceleration) were measured to evaluate motor performance, retention, and consolidation.

Main Results:

• cTBS significantly reduced practice-related improvements in motor performance.
• cTBS impaired motor retention, evidenced by decreased peak velocity and acceleration.
• cTBS did not affect motor consolidation, as performance remained unchanged 24 hours post-practice.

Conclusions:

• Inhibitory cTBS over M1 degrades early motor performance and retention of voluntary finger movements.
• Motor consolidation, the long-term stabilization of motor memory, is not affected by cTBS over M1.