Acupuncture

a therapeutic treatment defined as the insertion of needles into the body at specific points (ie

acupoints)

has growing in popularity world-wide to treat various diseases effectively

especially acute and chronic pain. In parallel

interest in the physiological mechanisms underlying acupuncture analgesia

particularly the neural mechanisms have been increasing. Over the past decades

our understanding of how the central nervous system and peripheral nervous system process signals induced by acupuncture has developed rapidly by using electrophysiological methods. However

with the development of neuroscience

electrophysiology is being challenged by calcium imaging in view field

neuron population and visualization

in vivo

. Owing to the outstanding spatial resolution

the novel imaging approaches provide opportunities to enrich our knowledge about the neurophysiological mechanisms of acupuncture analgesia at subcellular

cellular

and circuit levels in combination with new labeling

genetic and circuit tracing techniques. Therefore

this review will introduce the principle and the method of calcium imaging applied to acupuncture research. We will also review the current findings in pain research using calcium imaging from

in vitro

to

in vivo

experiments and discuss the potential methodological considerations in studying acupuncture analgesia.