Transcranial Direct Current Stimulation Targeting the Entire Motor Network Does Not Increase Corticospinal...

Area of Science:

• Neuroscience
• Motor Control
• Neuromodulation

Background:

• Transcranial direct current stimulation (tDCS) is used to modulate brain activity.
• Conventional tDCS targets the primary motor cortex, while motor network tDCS targets functionally connected regions.
• Previous studies suggested motor network tDCS may be more effective than conventional tDCS.

Purpose of the Study:

• To compare the effects of motor network tDCS and conventional tDCS on corticospinal excitability.
• To investigate if motor network tDCS offers superior enhancement of corticospinal excitability compared to conventional tDCS.
• To assess the variability in response to both tDCS protocols.

Main Methods:

• A randomized, single-blind, within-subject study was conducted with 21 healthy participants.
• Participants received motor network tDCS, 2 mA conventional tDCS, and sham tDCS.
• Corticospinal excitability was measured using transcranial magnetic stimulation (TMS) at various time points after stimulation.

Main Results:

• Neither motor network tDCS nor conventional tDCS significantly increased corticospinal excitability compared to sham stimulation.
• No evidence was found to support the superiority of motor network tDCS over conventional tDCS.
• Motor network tDCS exhibited similar susceptibility to inter- and intrasubject variability as conventional tDCS.

Conclusions:

• The findings do not support the enhanced efficacy of motor network tDCS over conventional tDCS for modulating corticospinal excitability.
• Both tDCS approaches appear to be subject to significant variability.
• Further research is needed to understand the factors influencing tDCS efficacy and variability.