High-frequency transcutaneous electrical nerve stimulation (TENS) differentially modulates sensorimotor cortices: an...

Area of Science:

• Neuroscience
• Motor Control
• Somatosensation

Background:

• Transcutaneous electrical nerve stimulation (TENS) is known to influence the excitability of both the central motor and somatosensory systems.
• Understanding TENS's specific effects on sensorimotor cortical excitability is crucial for therapeutic applications.

Purpose of the Study:

• To investigate the impact of high-frequency TENS on the excitability of sensorimotor cortices in a TENS-treated finger muscle.
• To compare the effects of TENS on the motor cortex and somatosensory cortex using magnetoencephalography (MEG).

Main Methods:

• High-frequency TENS was applied to the extensor digitorum muscle for 15 minutes.
• Subjects performed self-paced middle finger and thumb extension movements before and after TENS.
• Movement-related cortical magnetic fields (MRCF) were recorded using MEG to assess changes in cortical activity.

Main Results:

• TENS application led to a decrease in the motor field (MF) amplitude for the TENS-treated middle finger, while the untreated thumb showed no change.
• The motor evoked field (MEF1) amplitude decreased for both TENS-treated and untreated finger movements.
• The magnetic field sources indicated distinct locations and orientations for motor cortex (pre-central) and somatosensory cortex (post-central) activity.

Conclusions:

• High-frequency TENS modulates the excitability of a specific area within the motor cortex.
• TENS influences a broader region of the primary somatosensory cortex compared to the motor cortex.
• The effects of TENS on the primary somatosensory cortex and motor cortex differ in their extent and nature.