Improving motor performance without training: the effect of combining mirror visual feedback with transcranial direct...

Area of Science:

• Neuroscience
• Motor Control
• Rehabilitation Science

Background:

• Mirror visual feedback (MVF) is known to improve motor performance in the non-trained limb.
• Upregulating neural plasticity may further enhance motor learning.
• Primary motor cortex (M1) plays a crucial role in motor execution and learning.

Purpose of the Study:

• To investigate if anodal transcranial direct current stimulation (a-tDCS) can augment MVF-induced motor improvements in the untrained hand.
• To determine if enhancing right M1 plasticity with a-tDCS during right-hand training improves left-hand performance.
• To explore the synergistic effects of concurrent MVF and a-tDCS on motor skill acquisition.

Main Methods:

• Participants trained a ball-rotation task with their right (trained) or left (untrained) hand over two days.
• During right-hand training on day 1, one group received a-tDCS over the right M1, while a control group received sham tDCS (s-tDCS).
• A control experiment assessed the effect of a-tDCS without MVF on left-hand performance.

Main Results:

• The a-tDCS group showed significantly greater MVF-induced performance improvements in the left hand compared to the s-tDCS group.
• These performance gains were sustained on day 2, even without tDCS application.
• a-tDCS combined with MVF led to more pronounced left-hand improvements than a-tDCS alone.

Conclusions:

• Upregulating right M1 activity via a-tDCS effectively augments MVF-induced motor performance improvements in the untrained hand.
• Concurrent application of MVF and a-tDCS demonstrates synergistic and additive effects on motor learning of the contralateral limb.
• These findings have significant implications for developing novel neurorehabilitation strategies and advancing exercise science.