Transcranial direct current stimulation: before, during, or after motor training?

Area of Science:

• Neuroscience
• Motor Control
• Rehabilitation

Background:

• Noninvasive brain stimulation, like transcranial direct current stimulation (tDCS), is increasingly used to enhance motor training-induced plasticity.
• The optimal timing for applying tDCS in conjunction with motor therapy to maximize neuroplasticity and behavioral outcomes remains unclear.

Purpose of the Study:

• To determine the most effective timing (before, during, or after training) for applying transcranial direct current stimulation (tDCS) to enhance motor training-induced plasticity.

Main Methods:

• A randomized sham-controlled crossover trial involving 12 healthy participants.
• Participants underwent motor training with either active or sham tDCS applied before, during, or after the training sessions.
• Corticospinal excitability was measured using motor-evoked potentials (MEPs) from the first dorsal interosseous muscle via transcranial magnetic stimulation (TMS).

Main Results:

• Transcranial direct current stimulation (tDCS) applied *before* the motor training significantly enhanced corticospinal excitability compared to baseline and sham conditions.
• Applying tDCS *during* or *after* the motor training did not yield significant enhancements in corticospinal excitability.

Conclusions:

• The findings suggest that performing transcranial direct current stimulation (tDCS) *before* motor training is crucial for optimizing motor training-induced plasticity.
• This specific timing may be key for maximizing neuroplasticity and potential therapeutic benefits in motor rehabilitation.