Repetitive Transcranial Magnetic Stimulation Primed Self-controlled Practice on Motor Learning

Continuous theta-burst stimulation (cTBS) is a patterned form of rTMS consisting of bursts of three pulses at 50Hz, repeated every 200ms (5Hz), administered continuously without breaks. In this study, cTBS is delivered over the target cortical area according to established safety guidelines (e.g., a continuous 40s train for a total of 600 pulses) at an intensity set as a percentage of the resting motor threshold. The procedure is used to induce a transient reduction in cortical excitability as a priming intervention prior to motor practice.

Self-controlled practice is a motor learning intervention in which participants are granted autonomy to make choices about key aspects of their practice sessions (e.g., when to receive feedback, the sequence/timing of trials, or selection of specific practice parameters). This design allows participants to actively control elements of the training experience according to their preference, thereby fostering intrinsic motivation and engagement. The intervention is grounded in the OPTIMAL theory of motor learning, which highlights the role of autonomy support in enhancing learning outcomes and motivation. In this study, participants in the self-controlled practice group make their own decisions regarding practice conditions, in contrast to yoked controls who follow externally assigned parameters.

Sham TBS involves the application of a sham theta-burst stimulation protocol designed to mimic the sensory experience of active TBS without delivering effective magnetic pulses to the brain. This is typically achieved by angling the coil to prevent cortical stimulation. The procedure controls for placebo effects and participant expectations while ensuring blinding. The sham stimulation session matches the timing and setup of active TBS interventions but does not induce cortical excitability changes.

Yoked practice refers to a motor learning protocol in which participants perform tasks under externally controlled practice conditions, matched to the parameters (e.g., feedback) of a paired participant from a self-controlled practice group. This design removes participant autonomy over practice choices, allowing comparison between self-controlled and externally controlled practice to evaluate the effects of autonomy on motor learning and motivation.

Intermittent theta-burst stimulation (iTBS) is a patterned form of repetitive transcranial magnetic stimulation (rTMS) consisting of bursts of three pulses at 50Hz, repeated every 200ms (5Hz). In this study, iTBS is delivered over the target cortical area using standard protocols (e.g., 2s trains of TBS repeated every 10s for a total of 600 pulses) at an intensity set as a percentage of the resting motor threshold. The procedure aims to facilitate cortical excitability as a priming intervention prior to motor practice.