Moxibustion Stimulation Induces Changes in Brain Activity: A Functional MR Imaging Study

Acupuncture is believed to significantly modify neural circuits in the brain. However, the effects of moxibustion stimulation remain unclear. Therefore, we used functional MRI to investigate brain activation sites induced by moxibustion stimulation using an electric moxibustion device that mimics Japanese Tonetsu-kyu half-grain-sized direct moxibustion.

Twenty-two healthy adult participants underwent 6 rounds of 7-s moxibustion stimulations on the right acupuncture point ST36 using electric moxibustion during functional MRI measurement. The maximum output temperature of electric moxibustion was 67.5°C. However, the contact surface temperature was adjusted to 58.6 ± 0.1°C using cooking wrap to avoid small burns caused by heating. The ON time was divided into 3 periods: ON1, 2s from the start of moxibustion stimulation (<45°C); ON2, 5s from 2s after the start of output to the end of stimulation (>45°C); and ON3, 3s after the completion of stimulation. Each block was designed with all options other than ON set to OFF.

Common and different activations were observed in all ON times. During stimulation, common activation was observed in the insula, S1, and supramarginal gyrus. Activation in the central operculum, frontal operculum and supplementary motor area was observed only in the ON1 condition, while activation in the frontal pole, cerebellum, and right S2 was observed only in the ON2 condition. Using electric moxibustion that mimics a grain-sized direct moxa cone, common and different activations were confirmed from the start of output to 45°C and above 45°C, and the activation was sustained after the completion of stimulation.

This study showed that moxibustion could affect almost the same areas of pain-related regions. Based on the findings of this study, further research on moxibustion-induced brain activation may help elucidate the mechanism of its therapeutic effects.