Utilizing transcranial magnetic stimulation to study the human neuromuscular system

Area of Science:

• Neuroscience
• Human Physiology
• Biomedical Engineering

Background:

• Transcranial magnetic stimulation (TMS) has been utilized for over two decades, with significant growth in its application over the last ten years.
• A primary application of TMS is the investigation of human neuromuscular system physiology, plasticity, and function.
• Single pulse TMS to the motor cortex stimulates pyramidal neurons, yielding electromyographic responses crucial for evaluating corticospinal tract integrity.

Purpose of the Study:

• To demonstrate the methodological and technical aspects of single-pulse and paired-pulse TMS.
• To showcase the application of these TMS techniques on specific muscle groups: the flexor carpi radialis (FCR) and erector spinae (ES).
• To provide examples of how TMS can be used to study neuromuscular system function in research contexts, such as immobilization effects on muscle performance and low back pain.

Main Methods:

• Application of single-pulse TMS to the motor cortex to elicit motor evoked potentials.
• Utilizing paired-pulse TMS with varying interstimulus intervals to assess intracortical facilitatory and inhibitory mechanisms.
• Demonstrating these techniques on the flexor carpi radialis (FCR) and erector spinae (ES) muscles.

Main Results:

• Single-pulse TMS provides measurable electromyographic responses to assess corticospinal tract excitability.
• Paired-pulse TMS allows for the partitioning of cortical excitability by measuring intracortical facilitatory and inhibitory properties.
• The demonstrated techniques are applicable to various muscles within the human neuromuscular system.

Conclusions:

• TMS is a versatile and established technique for studying the human neuromuscular system.
• Single-pulse and paired-pulse TMS offer valuable insights into corticospinal excitability and intracortical processing.
• The presented methods serve as examples for applying TMS to investigate muscle function and related research questions.