Can brain stimulation enhance the effects of laser acupuncture on movement and brain activity?

This study involves the combined use of laser acupuncture and transcranial direct current stimulation (tDCS) to investigate their effects on brain excitability and motor threshold. Laser Acupuncture Therapy Laser acupuncture is a non-invasive therapeutic method that applies low-level laser therapy (LLLT) to acupuncture points to stimulate physiological responses. In this study, a low-level laser device will be used to irradiate the LI4 (Hegu) and LI11 (Quchi) acupoints bilaterally. The parameters for laser acupuncture are: Wavelength: 808 nm Power output: 100 mW Energy density: 4 J/cm² per point Mode: Continuous wave Duration: 5 minutes Transcranial Direct Current Stimulation (tDCS) tDCS is a non-invasive neuromodulation technique that delivers a constant, low-intensity electrical current to the scalp to modulate neuronal excitability. In this study, anodal tDCS will be applied over the primary motor cortex (M1), with the cathode placed over the contralateral supraorbital region. The stimulation parameters are: Intensity: 2 mA Duration: 20 minutes Electrode size: 5x7 cm (35 cm²) Current density: 0.043 mA/cm² Timing and Delivery: Laser acupuncture and tDCS will be administered simultaneously, with both interventions starting and ending at the same time. Frequency and Duration: Each participant will receive one session per condition, and there are three conditions in total (e.g., laser acupuncture alone, tDCS alone, and combined intervention), following a crossover design. Each session lasts approximately 120 minutes including setup and assessments. A washout period of at least 48 hours will be implemented between sessions to minimize carryover effects. Personnel: All interventions will be administered by a trained acupuncturist with experience in laser therapy, and a trained neurostimulation technician for tDCS procedures. Setting: All sessions will take place in a controlled university research laboratory at Monash University Peninsula Campus. Adherence and Fidelity Monitoring: Intervention adherence will be monitored by trained research staff using standardized treatment checklists. Fidelity to the protocol will be ensured through direct observation and regular supervision. Equipment logs will be maintained to record parameters and duration for each session.