[Instant adjustive effect of auricular electroacupuncture on brain default model network of patients with primary...

To investigate the immediate brain effect of auricular electroacupuncture (EA) in the treatment of primary insomnia (PI).

In this study, 15 subjects with PI who were diagnosed according to Pitsburgh Sleep Quality Index (PSQI), and other 15 age- and gender-matched subjects without insomnia were recruited in the present study. The PI patients received EA (4 Hz/20 Hz, a tolerable electrical current strength) of auricular concha for 30 min, and their resting state functional magnetic resonance imaging (fMRI) data before and after treatment were collected. The healthy subjects received no any treatment and their resting state fMRI data were collected. The diffe-rence of default mode network functional connectivity between the patients and healthy subjects, and changes of the patient's brain functional connectivity after EA treatment were estimated by using seed-point-based analysis (SPBA).

Analysis by taking the posterior cingulate gyrus as the seed-point showed that compared with the healthy participants before treatment, the patient's brain functional connectivity between the posterior cingulate gyrus and the right insula, or the inferior frontal gyrus of the right opercularis region, or the right rolandic operculum was increased. After 30 minutes' EA treatment, the functional connectivity between the posterior cingulate gyrus and the precuneus, the left angular gyrus, the left frontal superior gyrus, the left frontal middle cortex, the right temporalis inferior gyrus, the right temporalis middle gyrus or the left medial orbitofrontal cortex was decreased, while the functional connectivity between the posterior cingulate gyrus and the right lingual gyrus, or the cortex surrounding the right calcarine fissure was increased.

EA of auricular concha has an instant effect in modulating the brain default mode network in PI patients, which may be its brain mechanism underlying improvement of PI.