Acupuncture modulates spontaneous activities in the anticorrelated resting brain networks

Neuroimaging studies of acupuncture have demonstrated extensive signal attenuations in the core regions of a "default mode" network as well as signal potentiations in the regions of a "central-executive" network. We proposed that this acupuncture-related dichotomy may represent the anticorrelation in these intrinsic brain networks showing spontaneous fluctuations during rest. According to a plentiful clinical report, acupuncture can provide pain relief beyond the time it is being administrated; therefore, imaging its sustained effect (rather than acute effect) on the brain networks may further help elucidate the mechanisms by which acupuncture achieves its therapeutic effects. As an interface, the anterior insula (AI) has recently been shown to be a network hub, which initiates dynamic switching between these intrinsic networks. Here, we attempt to explore how acupuncture can modulate spontaneous coherences of these resting networks anchored by the AI. Using a spontaneous activity detection approach, we identified an AI-related dichotomy showing spontaneous activations in the CEN along with wide spontaneous deactivations located exclusively in the DMN. Following verum acupuncture, but not sham control, there was a prominently enhanced dichotomy in the CEN and DMN networks. More importantly, a long-lasting effect of acupuncture could further modulate intrinsic coherences of the wide interoceptive-autonomic areas, including the paralimbic regions and brainstem nuclei. These findings suggested that acupuncture may not only enhance the dichotomy of the anticorrelated resting networks, but also modulate a larger spatio-temporal extent of spontaneous activities in the salient interoceptive-autonomic network, contributing to potential actions in the endogenous pain-modulation circuits and homeostatic control mechanisms.