“Acupuncture Therapies and Neuroplasticity” is an annual special issue published in “Neural Plasticity.” You can find many scientific studies in this journal provided at:
https://www.hindawi.com/journals/np/acupuncture.therapies.neuroplasticity/
Medical acupuncture is based on physiology and neuroscience like this. From those studies, you can learn how acupuncture works.