Advances of application of modern techniques for screening the neural circuits associated with local stimulation of acupoints

It is well known that acupoints have an intricate connection with the nervous system. The specific mechanism of acupuncture in regulating the nervous system and exerting the therapeutic effect is one of the hottest and most difficult aspects in the field of acupuncture research. The regulation of acupuncture on the nervous system involves multi-target and multi-link neurofeedback, and how to find the critical effector neurons in this process is the primary concern. In the present article, we introduce some modern paradigms and methodologies for screening acupuncture-responsive effector neurons starting from elucidation of structural and functional connectivity between acupoints and neurons, for example, 1) neurovirus tracing techniques for studying the neuronal structural connections, and immediate early gene labeling for identifying functionally connected neuronal ensembles activated by acupuncture stimulation, 2) neuroimaging techniques for observing the impact of acupuncture on brain functional connections from a macroscopic perspective in real-time, 3) in vitro and in vivo electrophysiological recordings, as well as in vivo fiber-optics recording or two-photon calcium imaging for revealing the activity characteristics of activated neuronal ensembles, 4) analysis of the causal relationship between the key effect neurons, their neural circuit connections and the therapeutic effect of acupuncture by using multiple measures such as optogenetics and chemogenetics, etc. We should further strengthen the connection between the experimental research, basic theory exploration and clinical practice of acupuncture, accelerate the process of revealing the scientific connotations and promote the modernization and internationalization of acupuncture therapy.