Acupoints as Neuromodulation Interfaces: Translating Classical Body Maps into Neural Circuit Science

Background/Objectives: Modern acupuncture research commonly operationalizes acupoints as standardized sites for needling or electrical stimulation. Although this convention has improved reproducibility, it may obscure how classical acupoint and meridian systems have historically organized relationships among intervention sites, sensory phenomena, symptom patterns, and therapeutic responses. This article proposes an operational framework for examining selected acupoint regions as candidate neuromodulation interfaces. It reframes acupoint and meridian systems as relational body maps and operationalizes this perspective through a multidimensional stimulation-engagement-response model that distinguishes intervention features, target engagement, and downstream functional outcomes while accounting for individual context. Methods: The framework was developed to organize existing evidence, identify unresolved causal links, and generate prospective experimental tests, rather than to establish neural or physiological mechanisms that have already been demonstrated. The Baliao region, comprising bilateral BL31-BL34 over the posterior sacral foramina, was selected as the primary case because classical localization and pelvic symptom associations can be examined alongside sacral anatomy and neurophysiology within a single region. Relevant clinical and preclinical findings were evaluated in relation to potential neural targets, physiological engagement, functional outcomes, and alternative explanations. Results: Clinical and preclinical evidence suggests possible engagement of sacral afferent, spinal, autonomic, and pelvic-floor regulatory circuits. However, the evidence remains indirect, heterogeneous, and insufficient to establish equivalence with implantable sacral neuromodulation, a unique BL31-BL34 mechanism, or absolute point specificity. The framework clarifies what current evidence supports, identifies unresolved mechanistic links and alternative explanations, and proposes prospective strategies for testing target engagement and physiological relevance. Conclusions: This approach provides a staged research agenda for moving from descriptive associations toward prospective tests of parameter-dependent target engagement, physiological relevance, and, ultimately, biomarker-guided neuromodulation.