The effects of acupuncture on the brain networks for emotion and cognition: an observation of gender differences

Acupuncture modulates brain activity at the limbic-paralimbic-neocortical network (LPNN) and the default mode network (DMN). Since these brain networks show gender differences when mediating emotional and cognitive tasks, we thus hypothesize that women and men may also respond differently to acupuncture procedure at these brain regions. In order to test this hypothesis, we retrieved the data of 38 subjects, 19 females and 19 males, who had brain fMRI during acupuncture from previous studies and reanalyzed them based on sex status. Deactivation at the LPNN/DMN during needle manipulation of acupuncture was more extensive in females than in males, particularly in the posterior cingulate (BA31), precuneus (BA7m) and angular gyrus (BA39). The functional correlations between the right BA31 and pregenual cingulate (BA32), hippocampus or contralateral BA31 were significantly stronger in females than in males. The angular gyrus (BA39) was functionally correlated with BA31 in females; in contrast, it was anticorrelated with BA31 in males. Soreness, a major component of the psychophysical responses to needle manipulation, deqi, was correlated in intensity with deactivation of the angular gyrus in females; no such relationships were observed in males. In contrast to lesser deactivation at the LPNN/DMN networks, needle manipulation during acupuncture induced greater activation at the secondary somatosensory cortex and stronger functional connectivity with the anterior-middle cingulate (BA32/24) in males than in females. Our study suggests that brains with sex dimorphism may process the acupuncture stimulation differently between women and men.