Simultaneous CBF and BOLD mapping of high frequency acupuncture induced brain activity

This study mapped brain activity elicited by high frequency electroacupuncture by simultaneously using blood oxygenation level dependent (BOLD) and cerebral blood flow (CBF) contrasts. Forty subjects participated in the study, in which twenty ones were imaged during electrical acupoint stimulation (EAS) to the left LI4 acupoint at a maximal intensity without pain, and the others were with a minimal-EAS at a just detectible intensity. Both BOLD and CBF data were acquired simultaneously during alternating blocks of rest and stimulation. The results showed that the minimal-EAS mostly induced the activities in somatosensory region, including those in inferior parietal lobule, SII, insula, and thalamus. On the other hand, EAS activated more including also posterior middle cingulate cortex (pMCC), and deactivated superior temporal gyrus. Moreover, deactivation was found in posterior cingulated cortex (PCC), precuneus from BOLD and in culmen of cerebellum, caudate from CBF. The comparison between EAS and minimal-EAS revealed deactivation in the default mode network in both BOLD and CBF signals, activation in thalamus, insula, and caudal anterior cingulate cortex (ACC) in the CBF signal alone, and deactivation in putamen, rostral ACC and parahippocampal gyrus in the BOLD signal alone. This study provides, for the first time, simultaneous CBF and BOLD responses to high frequency EAS at the LI4 acupoint, revealing concordant and complementary insights into the neural effects of EAS, including modulation of subcortical structures and limbic system.